A drive unit includes an output shaft, a drive source, which causes the output shaft to rotate in a reciprocating manner within a first angular range, an arcuate movement portion, which performs arcuate movement about the axis of the output shaft as the shaft is rotated, a pivot shaft, and a lever member, which is rotational about the axis of the pivot shaft. As the arcuate movement portion performs arcuate movement, the lever member is rotated, in a reciprocating manner within a second angular range, while changing the engaging position with the arcuate movement portion.