Laser scanning microscope

Abstract

In order to allow precise observation of a specimen at an observation point with a desired depth without changing the working distance of an objective optical system while employing a simple configuration, a laser scanning microscope according to the present invention includes an objective lens having a plurality of optical elements that are disposed with gaps therebetween in an optical-axis direction and that condense laser light emitted from a light source onto a specimen and also having an adjustment ring that allows changing of the focal point by moving the optical elements in the optical-axis direction; a scanner that has a galvanometer mirror capable of oscillating about a predetermined oscillation axis and that scans the laser light condensed onto the specimen by the objective lens in accordance with an oscillation angle of the galvanometer mirror; a light detecting unit that obtains image information of the specimen on the basis of return light returned from the specimen scanned with the laser light; and a scanner controlling unit that controls the oscillation angle of the galvanometer mirror so as to maintain an observation range of the specimen observed by the light detecting unit on the basis of the positions of the optical elements moved by the adjustment ring.