In a plug hole cap of an ignition apparatus for an internal combustion engine, the plug hole cap has a high water resistant characteristic with respect to the plug hole, and is manufactured in low cost. The ignition apparatus includes a cylinder head cover for fixing an ignition coil, an ignition plug stored in a plug hole formed in the cylinder head cover, a plug hole cap for closing an upper portion of the plug hole and an air bleeding hole penetrating the plug hole cap, for communicating the plug hole with the atmosphere. In particular, a water resistant wall covers at least an outside of a peripheral portion of an air bleeding hole outlet of the plug hole cap.