Abstract: A bidirectional optical transceiver is disclosed. In the bidirectional optical transceiver, by implementing, as a stacked structure, an optical bench in which an optical system and an optical-transmitting module are installed and a multi-layer substrate with good thermal, electrical and high-resistance characteristics in which an optical-receiving module and a driving circuit for driving the optical-transmitting module are installed, thermal, electrical or optical crosstalk is prevented, high-speed transmission of transmission signals is possible through high-speed modulation thereof, and miniaturization is achieved.