diff --git a/src/accounting/forms.py b/src/accounting/forms.py
new file mode 100644
index 0000000..b315f60
--- /dev/null
+++ b/src/accounting/forms.py
@@ -0,0 +1,41 @@
+# The Mia! Accounting Flask Project.
+# Author: imacat@mail.imacat.idv.tw (imacat), 2023/3/22
+
+#  Copyright (c) 2023 imacat.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+"""The forms.
+
+"""
+from flask_wtf import FlaskForm
+from wtforms import StringField, ValidationError
+from wtforms.validators import DataRequired
+
+from accounting import db
+from accounting.locale import lazy_gettext
+from accounting.models import Currency
+
+CURRENCY_REQUIRED: DataRequired = DataRequired(
+    lazy_gettext("Please select the currency."))
+"""The validator to check if the currency code is empty."""
+
+
+class CurrencyExists:
+    """The validator to check if the account exists."""
+
+    def __call__(self, form: FlaskForm, field: StringField) -> None:
+        if field.data is None:
+            return
+        if db.session.get(Currency, field.data) is None:
+            raise ValidationError(lazy_gettext(
+                "The currency does not exist."))
diff --git a/src/accounting/journal_entry/forms/currency.py b/src/accounting/journal_entry/forms/currency.py
index 8d16101..4dbe5ee 100644
--- a/src/accounting/journal_entry/forms/currency.py
+++ b/src/accounting/journal_entry/forms/currency.py
@@ -24,31 +24,16 @@ from flask_babel import LazyString
 from flask_wtf import FlaskForm
 from wtforms import StringField, ValidationError, FieldList, IntegerField, \
     BooleanField, FormField
-from wtforms.validators import DataRequired
 
 from accounting import db
-from accounting.locale import lazy_gettext
-from accounting.models import Currency, JournalEntryLineItem
+from accounting.forms import CURRENCY_REQUIRED, CurrencyExists
 from accounting.journal_entry.utils.offset_alias import offset_alias
+from accounting.locale import lazy_gettext
+from accounting.models import JournalEntryLineItem
 from accounting.utils.cast import be
 from accounting.utils.strip_text import strip_text
 from .line_item import LineItemForm, CreditLineItemForm, DebitLineItemForm
 
-CURRENCY_REQUIRED: DataRequired = DataRequired(
-    lazy_gettext("Please select the currency."))
-"""The validator to check if the currency code is empty."""
-
-
-class CurrencyExists:
-    """The validator to check if the account exists."""
-
-    def __call__(self, form: FlaskForm, field: StringField) -> None:
-        if field.data is None:
-            return
-        if db.session.get(Currency, field.data) is None:
-            raise ValidationError(lazy_gettext(
-                "The currency does not exist."))
-
 
 class SameCurrencyAsOriginalLineItems:
     """The validator to check if the currency is the same as the