A laser scanning microscope includes a light source unit that emits laser light, a scanning unit that scans the laser light, an optical system that converges the laser light into a specimen, a light detecting unit that detects fluorescence generated from the specimen, and a filter unit located on an optical path of light entering the light detecting unit. The filter unit includes a short pass filter that has a large number of independent filter cells in different wavelength ranges formed in line on a common substrate, and a long pass filter that has a large number of independent filter cells in different wavelength ranges formed in line on a common substrate. The filter unit has a characteristic of a bandpass filter having a desired wavelength range owing to a combination of the filter cells of the short pass filter and the filter cells of the long pass filter.