A confocal microscope includes a light source that emits illuminating light beam, an illuminating optical system that irradiates the illuminating light beam onto a specimen, a condensing optical system that condenses the light reflected off the specimen and a light detection unit. The light detection unit includes a mask member, a movable shutter and a light detector. The mask member includes a plurality of reflecting/transmitting surfaces each constituting a light separating surface, and only the central portion of the light flux entering the mask member from the condensing optical system exits through a pinhole. The movable shutter opens or closes off a plurality of pinholes individually, and the light detector detects the light flux having passed through the pinholes.