A laser scanning microscope comprising: a light source that generates a multiwavelength laser beam containing plural wavelengths; a wavelength extracting unit that extracts a laser beam with one or more wavelength from the multiwavelength laser beam; an objective lens that focuses the laser beam on a sample; an optical scanning unit that performs a two-dimensional raster scan of the sample by repeatedly scanning each line of the raster scan by the laser beam before shifting the laser beam to the next line; a first focusing-position control unit that includes a wavefront modulator, the first focusing-position control unit being provided on an optical path of the laser beam, and shifting a focusing position of the laser beam on the sample in a direction of an optical axis of the objective lens to eliminate deviation in the focusing position of the laser beam with each wavelength in a direction of the optical axis with respect to the focusing position of the laser beam with a reference wavelength; a splitter element that splits an observation light from the optical path of the laser beam, the splitter element being arranged between the light source and the first focusing-position control unit, the observation light having a different wavelength from the laser beam and being emitted from the focusing position; a confocal detecting unit (24, 25a, 25b, 27, 28) that has a confocal aperture for a confocal detection of a light from the focusing position; a light selecting unit (23a, 23b) that selects the light detected by the confocal detecting unit (24, 25a, 25b, 27, 28); and a control unit that, in synchronization with the repeated scanning of one line by the optical scanning unit, controls the wavelength extracting unit to sequentially extract the laser beam with the plural wavelengths for each wavelength and to change the wavelength with each repetition of scanning the line, and controls the first focusing-position control unit to eliminate deviation of the focusing position along the optical axis corresponding to the wavelength of the extracted laser beam, and generates an image for each of the wavelengths of the laser beam extracted by the wavelength extracting unit for all lines of the two-dimensional raster scan, the image being based on a detection signal obtained from the confocal detecting unit (24, 25a, 25b, 27, 28) according to the laser scanning by the optical scanning unit. a light source that generates a multiwavelength laser beam containing plural wavelengths; a wavelength extracting unit that extracts a laser beam with one or more wavelength from the multiwavelength laser beam; an objective lens that focuses the laser beam on a sample; an optical scanning unit that performs a two-dimensional raster scan of the sample by repeatedly scanning each line of the raster scan by the laser beam before shifting the laser beam to the next line; a first focusing-position control unit that includes a wavefront modulator, the first focusing-position control unit being provided on an optical path of the laser beam, and shifting a focusing position of the laser beam on the sample in a direction of an optical axis of the objective lens to eliminate deviation in the focusing position of the laser beam with each wavelength in a direction of the optical axis with respect to the focusing position of the laser beam with a reference wavelength; a splitter element that splits an observation light from the optical path of the laser beam, the splitter element being arranged between the light source and the first focusing-position control unit, the observation light having a different wavelength from the laser beam and being emitted from the focusing position; a confocal detecting unit (24, 25a, 25b, 27, 28) that has a confocal aperture for a confocal detection of a light from the focusing position; a light selecting unit (23a, 23b) that selects the light detected by the confocal detecting unit (24, 25a, 25b, 27, 28); and a control unit that, in synchronization with the repeated scanning of one line by the optical scanning unit, controls the wavelength extracting unit to sequentially extract the laser beam with the plural wavelengths for each wavelength and to change the wavelength with each repetition of scanning the line, and controls the first focusing-position control unit to eliminate deviation of the focusing position along the optical axis corresponding to the wavelength of the extracted laser beam, and generates an image for each of the wavelengths of the laser beam extracted by the wavelength extracting unit for all lines of the two-dimensional raster scan, the image being based on a detection signal obtained from the confocal detecting unit (24, 25a, 25b, 27, 28) according to the laser scanning by the optical scanning unit.