PROBLEM TO BE SOLVED: To provide a technique that is mountable on an ophthalmic device as an attachment and can retain operability of the ophthalmic device, while saving an arrangement space.SOLUTION: The operation unit is mountable on the ophthalmic device. The operation unit includes a housing, and one or more contact members. The housing stores at least a part of the operation part for operating the ophthalmic device. The one or more contact members include contact parts respectively each of which comes into contact with a part of a bottom surface of the ophthalmic device with it mounted on the ophthalmic device, and are projectingly provided with respect to the housing.SELECTED DRAWING: Figure 6
