A projection lens includes a lens group holding tube including lenses on the side facing the inner circumference of the lens group holding tube, a cam tube that supports the lens group holding tube movably in the optical axis direction, and a guide tube that supports the cam tube rotatably around the optical axis. The lens group holding tube includes a guide pin that protrudes outward from the lens group holding tube. The cam tube has a cam hole which inclines with respect to the optical axis direction along the circumferential direction and through which the guide pin passes. The guide tube includes a guide groove which extends in the optical axis direction and into which the guide pin is so inserted as to pass through the inner circumference of the guide groove and a flange that protrudes outward.