PURPOSE: To maintain high stability and reliability enough to bear rough handling by controlling a cam operated clutch by means of a controlling shutter aggregate comprising a rotary actuator and balancing shutter blade.

CONSTITUTION: A cam operated clutch comprising inner and outer handles 20 and 12, piston aggregate 16, inner and outer side clutch plates 18 and 14 and a cam mechanism is controlled by a rotary actuator 60 and a shutter blade 58. This rotary actuator 60 has two pole pieces and is stabilized at two positions deflected at a small angle. At a position turned downward, the inner side clutch plate 18 is made to engage with the outer side clutch plate 14 by the blade end 76 of the shutter blade 58 to allow the outside handle 12 to mechanically activate a cam mechanism. In addition, at a position turned upward, both clutch plates 14 and 18 are not made to engage with each other. This constitution allows a clutch control mechanism to perform its control by only turning operation and can make it less sensitive to linear acceleration.