An ophthalmic laser surgical apparatus includes a laser source and an irradiation optical system with a beam expander unit. The beam expander unit includes a first lens unit, a second lens unit, and a plane-to-plane distance changing unit. The first lens unit is configured to change the focal length so as to change a spot size of a laser in a target position. The second lens unit includes at least one lens. The plane-to-plane distance changing unit is configured to change the distance between a principal plane of the first lens unit and a principal plane of the second lens unit so as to adjust one of divergence and convergence of the laser that has passed through the first lens unit.
