A confocal microscope unit (1A, 1B, 1C) attached to a connection port of a microscope including a microscope optical system to constitute a confocal microscope, the confocal microscope unit (1A, 1B, 1C) comprising: a first subunit including a light source outputting first excitation light, a first aperture limiting a luminous flux of first fluorescence generated from a sample to be observed in response to the first excitation light, and a first photodetector detecting the first fluorescence having passed through the first aperture; a second subunit including a light source outputting second excitation light, a second aperture limiting a luminous flux of second fluorescence generated from the sample in response to the second excitation light, and a second photodetector detecting the second fluorescence having passed through the second aperture; a scan mirror configured to scan the excitation light output from the first and second subunits (6a, 6b) on the sample via the microscope optical system and guide the fluorescence generated from the sample in response to the excitation light to the first and second subunits (6a, 6b); and a main housing configured to be attachable to the connection port and to which the scan mirror, the first subunit, and the second subunit are fixed, wherein the first subunit includes a first optical mirror configured to reflect the first excitation light and the first fluorescence and transmit the second excitation light and the second fluorescence, wherein the second subunit includes a second optical mirror configured to reflect the second excitation light and the second fluorescence, and wherein the first subunit and the second subunit are disposed in the main housing so that an incident angle of the first excitation light to the scan mirror is displaced from an incident angle of the second excitation light to the scan mirror by a predetermined angle (θ S), as a result of a disposition of the second subunit to be shifted from the first subunit in a direction perpendicular to a light guiding direction of the first fluorescence toward the first optical mirror based on centre positions of the first and second optical mirrors (9a, 9b). a first subunit including a light source outputting first excitation light, a first aperture limiting a luminous flux of first fluorescence generated from a sample to be observed in response to the first excitation light, and a first photodetector detecting the first fluorescence having passed through the first aperture; a second subunit including a light source outputting second excitation light, a second aperture limiting a luminous flux of second fluorescence generated from the sample in response to the second excitation light, and a second photodetector detecting the second fluorescence having passed through the second aperture; a scan mirror configured to scan the excitation light output from the first and second subunits (6a, 6b) on the sample via the microscope optical system and guide the fluorescence generated from the sample in response to the excitation light to the first and second subunits (6a, 6b); and a main housing configured to be attachable to the connection port and to which the scan mirror, the first subunit, and the second subunit are fixed, wherein the first subunit includes a first optical mirror configured to reflect the first excitation light and the first fluorescence and transmit the second excitation light and the second fluorescence, wherein the second subunit includes a second optical mirror configured to reflect the second excitation light and the second fluorescence, and wherein the first subunit and the second subunit are disposed in the main housing so that an incident angle of the first excitation light to the scan mirror is displaced from an incident angle of the second excitation light to the scan mirror by a predetermined angle (θ S), as a result of a disposition of the second subunit to be shifted from the first subunit in a direction perpendicular to a light guiding direction of the first fluorescence toward the first optical mirror based on centre positions of the first and second optical mirrors (9a, 9b).