A mounting structure of a decorative cap includes a door panel, a cylinder lock fixed to the door panel, and a decorative cap member. A protrusion portion of a cylinder lock protruding 5 from the door panel is covered with the decorative cap member. The decorative cap member includes a water guide channel guiding infiltrated water from a gap between a key insertion opening and a surface of the cylinder lock, to a water ejection opening which is opened on a peripheral wall. The key insertion opening 10 exposes a key insertion section of the cylinder lock.

A handle unit having a handle element for opening and/or closing a lock provided on a moving part includes a lock cylinder, which is protected by a covering cap, and an attachment element, on which the covering cap is releasably disposed. The covering cap has at least one guide projection on the interior thereof, which bears on a guide surface when in the snap-in position, which is formed on the attachment element and is complementary to the guide projection. The attachment element forcibly guides the movement of the covering cap when the covering cap is released, such that the at least one guide projection moves along the complementary guide surface, away from the attachment element.

A mounting structure of a decorative cap includes a door panel, a cylinder lock fixed to the door panel, and a decorative cap member. A protrusion portion of a cylinder lock protruding from the door panel is covered with the decorative cap member. The decorative cap member includes a water guide channel guding infiltrated water from a gap between a key insertion opening and a surface of the cylinder lock, to a water ejection opening which is opened on a peripheral wall. The key insertion opening exposes a key insertion section of the cylinder lock.

A handle unit having a handle element for opening and/or closing a lock provided on a moving part includes a lock cylinder, which is protected by a covering cap, and an attachment element, on which the covering cap is releasably disposed. The covering cap has at least one guide projection on the interior thereof, which bears on a guide surface when in the snap-in position, which is formed on the attachment element and is complementary to the guide projection. The attachment element forcibly guides the movement of the covering cap when the covering cap is released, such that the at least one guide projection moves along the complementary guide surface, away from the attachment element.