A hair condition-determining device can have a device body having at least one first region and one second region, wherein the first region and the second region are designed in such a way that the hair of the user can be moved between the first region and the second region, at least one optional light source arranged in or on the device body for illuminating the hair of the user, at least one optical sensor arranged in or on the device body for sensing light that has been emitted by the light source and has interacted with the hair and/or ambient light that has interacted with the hair, and an electronic circuit device arranged in or on the device body, wherein the electronic circuit device is coupled to the optical sensor in order to receive the detected light.