diff --git a/c_glib/arrow-glib/scalar.h b/c_glib/arrow-glib/scalar.h
index b7a2ddcde80a7..25f9156f85c02 100644
--- a/c_glib/arrow-glib/scalar.h
+++ b/c_glib/arrow-glib/scalar.h
@@ -518,7 +518,7 @@ GArrowDecimal32 *
 garrow_decimal32_scalar_get_value(GArrowDecimal32Scalar *scalar);
 
 #define GARROW_TYPE_DECIMAL64_SCALAR (garrow_decimal64_scalar_get_type())
-GARROW_AVAILABLE_IN_5_0
+GARROW_AVAILABLE_IN_19_0
 G_DECLARE_DERIVABLE_TYPE(
   GArrowDecimal64Scalar, garrow_decimal64_scalar, GARROW, DECIMAL64_SCALAR, GArrowScalar)
 struct _GArrowDecimal64ScalarClass