A cam element portion comprises a slant portion (reverse-rotation return slope portion), which is positioned on a rotary-delay side from a maximum-lift portion (lift ending point) of an end-face cam and slants inward toward the rotary-delay side from an outer peripheral face of the end-face cam. Accordingly, in a valve gear of an engine in which cams operative to control opening/closing of a valve are switchable, it can be properly prevented that the cam element portion is switched unexpectedly and improperly or an operational member breaks down which are possibly caused by an engine's reverse rotation.