A fluorescence laser scanning microscope, for scanning a laser over a specimen plane, comprising: a laser as a light source unit arranged to generate excitation light; two scanning units (11, 12) each arranged for scanning the excitation light from the light source unit across the specimen plane; and a detecting optical system having a detector arranged for detection of fluorescence light from the specimen plane, wherein an optical path between the light source unit and the specimen plane is selectable between two optical paths, each optical path including a respective one of the scanning units, characterised in that the detecting optical system has a dichroic mirror arranged for extraction of fluorescence light from light advancing in an opposite direction to the excitation light from the specimen plane along at least a part of each optical path of the optical paths, and in that a first scanning unit of the scanning units comprises a controllable galvanometer scanner arranged in a first optical path of the two optical paths and a second scanning unit of the scanning units comprises a resonant galvanometer scanner arranged in a second optical path of the two optical paths, wherein the optical path is selectable between the first optical path in which light from the light source unit advances to the specimen plane via the controllable galvanometer scanner and light from the specimen plane advances to the detector via the controllable galvanometer scanner and the second optical path in which light from the light source unit advances to the specimen plane via the resonant galvanometer scanner and light from the specimen plane advances to the detector via the resonant galvanometer scanner. a laser as a light source unit arranged to generate excitation light; two scanning units (11, 12) each arranged for scanning the excitation light from the light source unit across the specimen plane; and a detecting optical system having a detector arranged for detection of fluorescence light from the specimen plane, wherein an optical path between the light source unit and the specimen plane is selectable between two optical paths, each optical path including a respective one of the scanning units, characterised in that the detecting optical system has a dichroic mirror arranged for extraction of fluorescence light from light advancing in an opposite direction to the excitation light from the specimen plane along at least a part of each optical path of the optical paths, and in that a first scanning unit of the scanning units comprises a controllable galvanometer scanner arranged in a first optical path of the two optical paths and a second scanning unit of the scanning units comprises a resonant galvanometer scanner arranged in a second optical path of the two optical paths, wherein the optical path is selectable between the first optical path in which light from the light source unit advances to the specimen plane via the controllable galvanometer scanner and light from the specimen plane advances to the detector via the controllable galvanometer scanner and the second optical path in which light from the light source unit advances to the specimen plane via the resonant galvanometer scanner and light from the specimen plane advances to the detector via the resonant galvanometer scanner.