VALVE GEAR DEVICE

PURPOSE:To facilitate switching of valve operating characteristics by providing first and second locker arms whose respective ends are engaged with a low velocity ratio cam and a high velocity ratio cam provided on a cam shaft, and making the second locker arm switchable also to the state wherein it is separated from the fixed side in the state wherein it is supported freely rotatable on the fixed side. CONSTITUTION:To open/close two suction (exhaust) valves 2, 2 a pair of low velocity ratio cams 3, 3 and a high velocity ratio cam 4 positions between these came 3, 3 are formed on a cam shaft 1, and a locker arm 5 mounted to a carrier 6 fixed on a cylinder head is provided between these cams 3, 4 and the valve 2. The locker arm 5 is comprised of a pair of first locker arms 7, 7 and a second locker arm facing respective cams 3, 4. And, a switching means 14 that is used to selectively switch the cams 3, 4 is built in the carrier 6, and this switching means 14 is constructed so as to make an outer piston 19 in the form of bottomed cylinder supporting the second locker arm 8 freely rotatable capable of switching to the state wherein it is freely slidable and the state wherein it is impossible to slide.