diff --git a/ninja/openapi/docs.py b/ninja/openapi/docs.py
index c70fadd1..6b32c9bc 100644
--- a/ninja/openapi/docs.py
+++ b/ninja/openapi/docs.py
@@ -1,14 +1,14 @@
 import json
 from abc import ABC, abstractmethod
 from pathlib import Path
-from typing import TYPE_CHECKING, Any, Optional
+from typing import TYPE_CHECKING, Any, Callable, Iterator, Optional, Union
 
 from django.conf import settings
 from django.http import HttpRequest, HttpResponse
 from django.shortcuts import render
 from django.urls import reverse
 
-from ninja.constants import NOT_SET
+from ninja.router import Router
 from ninja.types import DictStrAny
 
 if TYPE_CHECKING:
@@ -102,10 +102,25 @@ def _render_cdn_template(
     return HttpResponse(html)
 
 
-def _csrf_needed(api: "NinjaAPI") -> bool:
-    if api.csrf:
-        return True
-    if not api.auth or api.auth == NOT_SET:
-        return False
+def _iter_auth_callbacks(
+    api_or_router: Union["NinjaAPI", Router],
+) -> Iterator[Callable[..., Any]]:
+    """this is helper to iterate over all operations in api or router"""
+    if isinstance(api_or_router, Router):
+        for _, path_view in api_or_router.path_operations.items():
+            for operation in path_view.operations:
+                yield from operation.auth_callbacks
+    for _, router in api_or_router._routers:  # noqa
+        yield from _iter_auth_callbacks(router)
+
 
-    return any(getattr(a, "csrf", False) for a in api.auth)  # type: ignore
+def _csrf_needed(api: "NinjaAPI") -> bool:
+    add_csrf: Optional[bool] = getattr(api, "_add_csrf", None)
+    if add_csrf is not None:
+        return add_csrf
+    for auth_callback in _iter_auth_callbacks(api):
+        if getattr(auth_callback, "csrf", False):
+            api._add_csrf = True  # type: ignore[attr-defined]
+            return True
+    api._add_csrf = False  # type: ignore[attr-defined]
+    return False
diff --git a/tests/test_csrf.py b/tests/test_csrf.py
index eeab4884..17d5198a 100644
--- a/tests/test_csrf.py
+++ b/tests/test_csrf.py
@@ -3,7 +3,7 @@
 from django.conf import settings
 from django.views.decorators.csrf import csrf_exempt
 
-from ninja import NinjaAPI
+from ninja import NinjaAPI, Router
 from ninja.security import APIKeyCookie, APIKeyHeader
 from ninja.testing import TestClient as BaseTestClient
 
@@ -98,40 +98,97 @@ def test_view(request):
     assert response.status_code == 200, response.content
 
 
-def test_docs():
+def test_docs_add_csrf():
     "Testing that docs are initializing csrf headers correctly"
 
-    api = NinjaAPI(csrf=True)
+    class CookieAuth(APIKeyCookie):
+        def authenticate(self, request, key):
+            return key == "test"
+
+    api = NinjaAPI(csrf=False, auth=CookieAuth())  # `csrf=False` should be ignored
+
+    @api.get("/test")
+    def test_view(request):
+        return {"success": True}
 
     client = TestClient(api)
+
     resp = client.get("/docs")
     assert resp.status_code == 200
     csrf_token = re.findall(r'data-csrf-token="(.*?)"', resp.content.decode("utf8"))[0]
     assert len(csrf_token) > 0
 
-    api.csrf = False
+    assert hasattr(api, "_add_csrf")  # `api._add_csrf` should be set as cache
+
     resp = client.get("/docs")
     assert resp.status_code == 200
     csrf_token = re.findall(r'data-csrf-token="(.*?)"', resp.content.decode("utf8"))[0]
-    assert len(csrf_token) == 0
+    assert len(csrf_token) > 0
 
 
-def test_docs_cookie_auth():
+def test_docs_add_csrf_by_operation():
+    "Testing that docs are initializing csrf headers correctly"
+
     class CookieAuth(APIKeyCookie):
         def authenticate(self, request, key):
             return key == "test"
 
-    class HeaderAuth(APIKeyHeader):
+    api = NinjaAPI(csrf=False)  # `csrf=False` should be ignored
+
+    @api.get("/test1", auth=CookieAuth())
+    def test_view1(request):
+        return {"success": True}
+
+    @api.get("/test2")
+    def test_view2(request):
+        return {"success": True}
+
+    client = TestClient(api)
+    resp = client.get("/docs")
+    assert resp.status_code == 200
+    csrf_token = re.findall(r'data-csrf-token="(.*?)"', resp.content.decode("utf8"))[0]
+    assert len(csrf_token) > 0
+
+
+def test_docs_add_csrf_by_sub_router():
+    "Testing that docs are initializing csrf headers correctly"
+
+    class CookieAuth(APIKeyCookie):
         def authenticate(self, request, key):
             return key == "test"
 
-    api = NinjaAPI(csrf=False, auth=CookieAuth())
+    api = NinjaAPI(csrf=False)  # `csrf=False` should be ignored
+
+    @api.get("/test1", auth=CookieAuth())
+    def test_view1(request):
+        return {"success": True}
+
+    router = Router()
+
+    @router.get("/test2")
+    def test_view2(request):
+        return {"success": True}
+
+    api.add_router("/router", router)
+
     client = TestClient(api)
     resp = client.get("/docs")
+    assert resp.status_code == 200
     csrf_token = re.findall(r'data-csrf-token="(.*?)"', resp.content.decode("utf8"))[0]
     assert len(csrf_token) > 0
 
-    api = NinjaAPI(csrf=False, auth=HeaderAuth())
+
+def test_docs_do_not_add_csrf():
+    class HeaderAuth(APIKeyHeader):
+        def authenticate(self, request, key):
+            return key == "test"
+
+    api = NinjaAPI(csrf=True, auth=HeaderAuth())  # `csrf=True` should be ignored
+
+    @api.get("/test")
+    def test_view(request):
+        return {"success": True}
+
     client = TestClient(api)
     resp = client.get("/docs")
     csrf_token = re.findall(r'data-csrf-token="(.*?)"', resp.content.decode("utf8"))[0]