A slit lamp microscope of an embodiment comprises a light source, pair of slit blades, actuator, mechanism, operation part, storage, operation-content detector and controller. The light source emits illumination light. The pair of slit blades generates slit light from the illumination light. The mechanism changes the interval between the slit blades based on a driving force generated by the actuator. The storage stores in advance correspondence information in which the operation content with respect to the operation part and the operation amount of the actuator are associated. The operation-content detector detects an operation content with respect to the operation part. The controller obtains the operation amount associated with the detected operation content based on the correspondence information and control the actuator based on the obtained operation amount, thereby changing the interval of the slit blades by a distance corresponding to this operation content.
