The apparatus has a lens supporting unit which supports one side of a lens holder holding one lens forming a part of an expander lens with a plurality of plate springs, a lens driving unit which apply a driving force to the lens holder utilizing an electromagnetic force, and a solenoid which allows a plunger to be abutted and spaced on and from a surface on one side of the lens holder, with an elastic member interposed therebetween, in a position in the middle of a plurality of connecting regions where the plate springs are respectively connected.