A semiconductor laser drive circuit controlling a semiconductor laser diode connected to an output terminal by providing a drive electric current to the semiconductor laser diode includes: a constant electric current source configured to provide an electric current to the output terminal, the constant electric current source being connected to a first electric power terminal and the output terminal; a current sinking circuit connected to the output terminal and a second electric power terminal; a current sourcing circuit configured to provide a predetermined electric current to the output terminal or the current sinking circuit, the current sourcing circuit being connected to the first electric power terminal and the output terminal; and a terminating resistor having a resistance component equal to that of the semiconductor laser diode, the terminating resistor being connected to the circuit sinking circuit and the current sourcing circuit.