Provided are a passive Q-switch element, etc., with which, in a Q-switch pulse laser, etc., which oscillates in a plurality of higher-order modes, mode selection is possible without increasing the number of components within a resonator, and application is possible even in a waveguide laser with which spatial mode control is not possible. A passive Q-switch element, passive Q-switch laser device, planar waveguide passive Q-switch element, and passive Q-switch laser device are made to combine a saturable absorption body (2) and a transparent material (3) which is transparent to a laser oscillation wavelength, etc., and to hold a mode selection function in the passive Q-switch element.