A scanning optical microscope using a wavefront converting element suffers minimum off-axis performance degradation and allows the wavefront converting element to be controlled by a simple method. Further, a pupil relay optical system is simple in arrangement or unnecessary. A laser scanning microscope includes a laser oscillator and a wavefront converting element for applying a desired wavefront conversion to a laser beam emitted from the laser oscillator. An objective collects a wavefront-converted approximately parallel laser beam emerging from the wavefront converting element onto a sample. A detector detects signal light emitted from the sample. An actuator scans the objective along a direction perpendicular to the optical axis.