diff --git a/src/common/zk.cpp b/src/common/zk.cpp
index a23cb44ce..de69d552b 100644
--- a/src/common/zk.cpp
+++ b/src/common/zk.cpp
@@ -44,7 +44,10 @@ namespace jubatus{
     }
     
     do{
-      zh_ = zookeeper_init(hosts.c_str(), NULL, timeout, 0, NULL, 0);
+      // FIXME?: this loop will call zookeeper_init many times till
+      // the state got ZOO_CONNECTING_STAT
+      // timeout is supposed to be ms??
+      zh_ = zookeeper_init(hosts.c_str(), NULL, timeout * 1000, 0, NULL, 0);
       if(zh_ == NULL){
 	perror("");
 	throw std::runtime_error("cannot init zk");
diff --git a/src/common/zk.hpp b/src/common/zk.hpp
index b4c77488b..50867adae 100644
--- a/src/common/zk.hpp
+++ b/src/common/zk.hpp
@@ -34,7 +34,8 @@ namespace jubatus{
   // TODO: write zk mock and test them all?
   class zk{
   public:
-    zk(const std::string& hosts, int timeout = 1024, const std::string& logfile = "");
+    // timeout [ms]
+    zk(const std::string& hosts, int timeout = 10, const std::string& logfile = "");
     ~zk();
 
     void create(const std::string& path, const std::string& payload = "", bool ephemeral = false);
diff --git a/src/server/classifier.cpp b/src/server/classifier.cpp
index 31205d7fb..837ec9d67 100644
--- a/src/server/classifier.cpp
+++ b/src/server/classifier.cpp
@@ -58,7 +58,7 @@ int main(int argc, char *argv[])
   cmdline::parser p;
   p.add<int>("rpc-port", 'p', "port number", false, 9199);
   p.add<int>("thread", 'c', "thread number", false, 2);
-  p.add<int>("timeout", 't', "time out", false, 10);
+  p.add<int>("timeout", 't', "time out (sec)", false, 10);
   p.add<std::string>("storage", 'S', "storage type", false, "local");
   p.add<std::string>("zookeeper", 'z', "zookeeper location", false);
   p.add<std::string>("name", 'n', "learning machine instance name", true);