A rotation transfer mechanism includes a rotatable ring including an annular
gear
portion on an outer peripheral surface thereof; a rotation transfer gear including
a gear portion engageable with the annular gear portion and a rotation limit portion
engageable with an outer edge of the annular gear portion to prohibit the rotation
transfer gear from rotating; and a driven member drivable by a rotation of the
rotation transfer gear. The rotation transfer gear and the rotatable ring are positioned
relative to each other such that the gear portion and the annular gear portion
are engaged with each other when the rotatable ring performs a fixed-position rotating
operation, and such that the rotation limit portion faces the annular gear portion
and is configured to contact the outer edge of the annular gear portion when the
rotatable ring performs an advancing/retracting operation.