An optical module includes: a first circuit board on which a connector socket is mounted, an optical transceiver module that is electrically connected to the first circuit board via the connector socket; a heat sink; and a heat dissipating sheet. The optical transceiver module includes: a second circuit board on which an E/O converter, a drive circuit for the E/O converter, an O/E converter, and a current-to-voltage conversion circuit for the O/E converter are mounted; and an optical waveguide that guides an optical signal generated by the E/O converter to an output end of the optical transceiver module, and that guides an input optical signal to the O/E converter. The heat sink is thermally coupled to the E/O converter, the drive circuit, the O/E converter, and the current-to-voltage conversion circuit via the heat dissipating sheet, and presses the optical transceiver module onto the first circuit board.