MICROSCOPE

A microscope includes: an illumination optical system that focuses illumination light and forms an illumination region on a sample; a detection optical system that forms an image by light from the sample on an image plane; an aberration setting unit that sets an aberration state of at least one of the illumination optical system and the detection optical system; a detector in which a detection surface having a plurality of aligned detection units is arranged on the image plane; a calculation unit that calculates light amount distribution information of a detection image detected by the detection units; and a computation unit that determines an aberration state of at least one of the systems which should be set by the aberration setting unit based on the light amount distribution information of the detection image in a plurality of aberration states set by the aberration setting unit.