To provide a clutch structure capable of changing a direction of connection and disconnection, setting its rotation speed, peventing connection in both directions at the stop moment, and making an output rotation speed exceed an input rotation speed.

Power is transmitted to a jacket pipe provided with recession grooves having annular notches with difference depths, a plurality of roller parts are placed around the jacket pipe, the jacket pipe is put into a driving disk, a rotation ring corresponding to the recession grooves is placed between the jacket pipe and the driving disk, the rotation ring is placed in the recession grooves of the jacket pipe, so called as an operation block, the clutch structure is annularly arranged on one side of the rotation ring, and is combined with another braking ring having hart shaped sliding grooves, roller balls and an annular spring are fitted therebetween to transmit the power to the driving disk by matching the rotation ring with operation of the jacket pipe. Thus, this clutch structure allows to transmit the power in a unidirection or bidirection, and to set a rotation speed of connection and disconnection, thereby producing advantages of hardly generating idling in a bidrection and slipping after starting, and providing fast and stable starting.