Abstract: A bus terminating circuit is provided on each of a plurality of SCSI devices connected to each other through an SCSI bus line. A first terminating resistor is inserted between each of the signal lines and a power source line of the bus line and a second terminating resistor is inserted between each of the signal lines and ground. A first transistor is connected between the first terminating resistor and the power source line and a second transistor is connected between the second terminating resistor and ground. The first and second transistors are turned-on or off in response to an ON signal or an OFF signal inputted from an external terminal so that the first and second resistors can be connected or disconnected to or from the bus line.