Abstract: A mechanism for actuating a non-slidable disk type valve, which comprises a hollow cam body having a specific guide groove and axially slidable without rotation within a stationary casing, a cam follower relatively movably engaged with the guide groove and carried on a rear end of an output shaft which is supported rotatably and inclinably by a bearing member inclinably supported by the casing, a valve drive shaft supporting a disk-shaped valve body via a crank and supported on a machine frame so as to be co-rotatable and co-inclinable with the output shaft, a connector socket extending forward from the bearing member into engagement with the valve drive shaft so as to slightly push down or raise up the valve drive shaft thereby to urge the valve body toward or away from a valve seat so that the valve takes its closing position or its preparatory position before the valve is rotated to take its releasing position.