A hair-growth adjusting light emitting device includes a device body, a light-emitting unit attached to the device body, and a locking unit for locking the light-emitting unit to the device body. The device body has a main capacitor, a device body connector, an electric power switch, a release switch, and an electric power supplying part. The light-emitting unit has a light-emitting body and a light-emitting body side connector. Furthermore, the hair-growth adjusting light emitting device includes a release restriction mechanism for preventing the light-emitting unit from being released by the release button when the electric power switch is at a power-on position where the electric power supplying part feeds the electric power to the main connector, and a power-on restriction mechanism for preventing the electric power switch from moving to the power-on position when the light-emitting unit is detached from the device body.
