A confocal optical scanner includes: a plurality of condenser elements each configured to concentrate illumination light to be applied on a sample to produce fluorescence from the sample; a plurality of optical scanning units including a plurality of openings each configured to allow the illumination light concentrated by the condenser element to pass the opening, the optical scanning units each configured to scan the sample with the illumination light that has passed through the opening; a moving mechanism configured to move the optical scanning units to select one of the optical scanning units; and an incident-angle adjusting part configured to adjust the incident angle of the illumination light incident on the optical scanning unit selected from the optical scanning units according to the selected optical scanning unit.