A dehumidifier for a vehicle lamp is provided which includes, a dehumidification case that is coupled to a lamp housing through the interior and exterior of the lamp. The dehumidifier includes a plurality of connected chambers and a suction path connected to the interior of the lamp and a discharge path connected to the exterior of the lamp. Further, a thermoelement is coupled to the connection part and has a first and second surface exposed to different chambers. An absorbent is disposed within the chambers and a valve is disposed within the suction path and the discharge path. A controller is configured to adjust the supply and direction of current and open and close the valve. The dehumidifier continuously removes moisture formed within the lamp, while alternately drying an absorbent disposed within a first chamber and an absorbent disposed within a second chamber using a thermoelement.