PURPOSE: To prevent generation of a hammering noise and abnormal abrasion by certainly link switching a valve lift characteristic in a valve action device of an engine to switch the valve lift characteristic at the time of low and high rotation.

CONSTITUTION: A locker arm one end of which is linked to a valve V and which is driven by a cam 21 for low speed and a free cam follower 2 driven by a cam 22 for high speed are provided, and a lever member 7 oscillated to switch over to a first position to display a function of a lost motion mechanism by a hydraulic action plunger 31 and to a second position engaged with the free cam follower 2 and to stop the function of the lost motion mechanism is provided supported by the locker arm. Additionally, first and second engagement grooves 31, 31 are formed on the outer periphery of the action plunger 31, and a timing plate 51 to engage and disengage with these grroves in correspondence with oscillation of the locker arm is supported by the locker arm.