diff --git a/library/src/main/java/co/kyash/vtl/validators/MinLengthValidator.kt b/library/src/main/java/co/kyash/vtl/validators/MinLengthValidator.kt
new file mode 100644
index 0000000..df149da
--- /dev/null
+++ b/library/src/main/java/co/kyash/vtl/validators/MinLengthValidator.kt
@@ -0,0 +1,52 @@
+package co.kyash.vtl.validators
+
+import android.content.Context
+import co.kyash.vtl.VtlValidationFailureException
+import io.reactivex.Completable
+import io.reactivex.schedulers.Schedulers
+
+/**
+ * Validation error when the text length is shorter
+ */
+class MinLengthValidator(
+        private val errorMessage: String,
+        private val minLength: Int,
+        private val trim: Boolean = true
+) : VtlValidator {
+
+    /**
+     * Validate and return completable
+     *
+     * @param context
+     * @param text
+     * @return Completable
+     * @throws Exception which contains the error message
+     */
+    override fun validateAsCompletable(context: Context, text: String?): Completable {
+        return Completable.fromRunnable {
+            if (!validate(text)) {
+                throw VtlValidationFailureException(errorMessage)
+            }
+        }.subscribeOn(Schedulers.computation())
+    }
+
+    /**
+     * Validate immediately
+     *
+     * @param text
+     * @return result
+     */
+    override fun validate(text: String?): Boolean {
+        return text?.let {
+            if (trim) it.trim() else it
+        }?.length ?: 0 >= minLength
+    }
+
+    /**
+     * @return error message
+     */
+    override fun getErrorMessage(): String {
+        return errorMessage
+    }
+
+}
\ No newline at end of file
diff --git a/library/src/main/java/co/kyash/vtl/validators/RequiredValidator.kt b/library/src/main/java/co/kyash/vtl/validators/RequiredValidator.kt
index a624091..c46d3e5 100644
--- a/library/src/main/java/co/kyash/vtl/validators/RequiredValidator.kt
+++ b/library/src/main/java/co/kyash/vtl/validators/RequiredValidator.kt
@@ -10,7 +10,8 @@ import io.reactivex.schedulers.Schedulers
  * Validation error when the text is empty.
  */
 class RequiredValidator(
-        private val errorMessage: String
+        private val errorMessage: String,
+        private val trim: Boolean = true
 ) : VtlValidator {
 
     /**
@@ -36,7 +37,7 @@ class RequiredValidator(
      * @return result
      */
     override fun validate(text: String?): Boolean {
-        return !TextUtils.isEmpty(text)
+        return !TextUtils.isEmpty(text?.let { if (trim) it.trim() else it })
     }
 
     /**
diff --git a/library/src/test/java/co/kyash/vtl/validators/MinLengthValidatorTest.kt b/library/src/test/java/co/kyash/vtl/validators/MinLengthValidatorTest.kt
new file mode 100644
index 0000000..d41c54f
--- /dev/null
+++ b/library/src/test/java/co/kyash/vtl/validators/MinLengthValidatorTest.kt
@@ -0,0 +1,71 @@
+package co.kyash.vtl.validators
+
+import android.content.Context
+import co.kyash.vtl.testing.RxImmediateSchedulerRule
+import junit.framework.Assert.assertEquals
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.ParameterizedRobolectricTestRunner
+import org.robolectric.RuntimeEnvironment
+
+@Suppress("unused")
+@RunWith(ParameterizedRobolectricTestRunner::class)
+class MinLengthValidatorTest(
+        private val text: String?,
+        private val trim: Boolean,
+        private val result: Boolean,
+        private val errorMessage: String?
+) {
+
+    companion object {
+        private val MIN_LENGTH = 5
+        private val ERROR_MESSAGE = "This field has error"
+
+        @JvmStatic
+        @ParameterizedRobolectricTestRunner.Parameters
+        fun data(): List<Array<out Any?>> {
+            return listOf(
+                    // Failure
+                    arrayOf(null, true, false, ERROR_MESSAGE),
+                    arrayOf("", true, false, ERROR_MESSAGE),
+                    arrayOf("     ", true, false, ERROR_MESSAGE),
+                    arrayOf("abcd", true, false, ERROR_MESSAGE),
+
+                    // Success
+                    arrayOf("     ", false, true, null),
+                    arrayOf("abcde", true, true, null),
+                    arrayOf("abcdef", true, true, null)
+            )
+        }
+    }
+
+    @get:Rule
+    val rxImmediateSchedulerRule = RxImmediateSchedulerRule()
+
+    private lateinit var subject: VtlValidator
+
+    private val context: Context = RuntimeEnvironment.application
+
+    @Before
+    @Throws(Exception::class)
+    fun setUp() {
+        subject = MinLengthValidator(ERROR_MESSAGE, MIN_LENGTH, trim)
+    }
+
+    @Test
+    fun validate() {
+        assertEquals(result, subject.validate(text))
+    }
+
+    @Test
+    fun validateAsCompletable() {
+        if (errorMessage == null) {
+            subject.validateAsCompletable(context, text).test().assertNoErrors().assertComplete()
+        } else {
+            subject.validateAsCompletable(context, text).test().assertErrorMessage(errorMessage)
+        }
+    }
+
+}
\ No newline at end of file
diff --git a/library/src/test/java/co/kyash/vtl/validators/RequiredValidatorTest.kt b/library/src/test/java/co/kyash/vtl/validators/RequiredValidatorTest.kt
index 01aef9e..1cade35 100644
--- a/library/src/test/java/co/kyash/vtl/validators/RequiredValidatorTest.kt
+++ b/library/src/test/java/co/kyash/vtl/validators/RequiredValidatorTest.kt
@@ -14,6 +14,7 @@ import org.robolectric.RuntimeEnvironment
 @RunWith(ParameterizedRobolectricTestRunner::class)
 class RequiredValidatorTest(
         private val text: String?,
+        private val trim: Boolean,
         private val result: Boolean,
         private val errorMessage: String?
 ) {
@@ -25,9 +26,16 @@ class RequiredValidatorTest(
         @ParameterizedRobolectricTestRunner.Parameters
         fun data(): List<Array<out Any?>> {
             return listOf(
-                    arrayOf(null, false, ERROR_MESSAGE),
-                    arrayOf("", false, ERROR_MESSAGE),
-                    arrayOf("konifar", true, null)
+                    // Failure
+                    arrayOf(null, true, false, ERROR_MESSAGE),
+                    arrayOf("", true, false, ERROR_MESSAGE),
+                    arrayOf(" ", true, false, ERROR_MESSAGE),
+                    arrayOf("　", true, false, ERROR_MESSAGE),
+
+                    // Success
+                    arrayOf(" ", false, true, null),
+                    arrayOf("　", false, true, null),
+                    arrayOf("konifar", true, true, null)
             )
         }
     }
@@ -42,7 +50,7 @@ class RequiredValidatorTest(
     @Before
     @Throws(Exception::class)
     fun setUp() {
-        subject = RequiredValidator(ERROR_MESSAGE)
+        subject = RequiredValidator(ERROR_MESSAGE, trim)
     }
 
     @Test