PURPOSE: To provide a rotary clutch which transmits driving force from a driving source side to a driven side without loss and does not transmit torque from the driven side to the driving source side.

CONSTITUTION: One side rotary body 1 or 2 is rotated by a driving source to engage an engaging part 11b with a first locking part 22a so as to rotate the rotary body 2 or 1 of a driven side. After the rotary body 1 or 2 of the driving source side is rotated by a specified quantity, it is reversely rotated to separate the engaging part 11b from the first locking part 22a. The engaging part 11b is brought into contact with an initial movement cam face 23a to be displaced to an idling track 31 and then stopped. When the rotary body 1 or 2 is rotated in the reverse direction from the driven side, the engaging part 11b is moved in the idling track 31, passes outside of the first locking part 22a, and is brought into contact with a first track changing cam face 24a to be displaced to an engagement track 32. After the engaging part 11b rotates on the engagement track 32 by nearly one rotation, it is brought into contact with a first engaging cam face 22b and displaced from the engagement track 32 to be engaged with the first locking part 22a.