To provide a bi-directional transmission circuit where a plurality of transceiver elements transmit and receive signal through a transmission bus, capable of performing high-speed transmission and reducing power consumption simultaneously while suppressing signal reflection.

When a first transceiver element 10 operates as a transmitting side, a first control unit 17 sets connection to a first termination voltage source 15 through a first termination resistance 14 of a transmission bus 2 by a first switch to OFF, while a second control unit 27 sets connection to a second termination voltage source 25 through a second termination resistor 24 of the transmission bus 2 by a second switch 26 to ON.