A blur correcting device comprises: a blur correction optical system that
corrects an image blur by moving along a direction substantially
perpendicular to an optical axis; a locking member that locks the blur
correction optical system when an image blur correction is not executed;
and a lock drive device having an elongated external shape with a length
thereof set along a direction in which a tangential line of a circle
having a center thereof at the optical axis extends on a plane
substantially perpendicular to the optical axis, which generates a drive
force to drive the locking member.
