To provide a simple and small rotation transmission mechanism.

This rotation transmission mechanism comprises a rotatingly driving shaft and an annular rotating body inserted into the rotatingly driving shaft and rotatably held on the shaft in a specified deviated angle state. An elongated hole is formed in the rotatingly driving shaft at the annular rotating body mounting portion along the axial direction thereof. A pin passed through the center of the annular rotating body and along the radial direction thereof is passed through the elongated hole.