In one embodiment of a data storage device, the inside of its housing 111 is divided into first and second spaces 1 and 2 by a chassis 110. The data storage device includes at least one optical pickup 104 that writes data on a storage medium and a heat radiating member 109 which is thermally coupled to the optical pickup 104 to transfer the heat generated by the optical pickup 104. The optical pickup 104 and the heat radiating member 109 are arranged in the first and second spaces 1 and 2, respectively.