A fluorescence microscope 11 includes an objective lens 101, a dichroic mirror 102, a half mirror 105, a mirror 106, a laser light source 111, an ND filter 112, a beam expander 113, a mirror 114, a spatial light modulator 115, a lens 131, a band pass filter 132, a spatial light modulator 133, and a detector, etc. The spatial light modulator 115 can vary its spatial light modulation, and can set the number, positions, and shapes of regions to be irradiated with excitation light in the determined specimen 1 by irradiating the determined specimen 1 with spatially modulated excitation light via the subsequent optical system.