Semiconductor laser module, and method for driving the semiconductor laser module

The invention provides a semiconductor laser module which can suppress overcurrent flowing into a thermo-module, wherein the thermo-module ( 5 ) carries out a heating action when a reverse current flows from lead pin ( 16 f) through lead pin ( 16 a), and contrarily carries out a cooling action when a current flows from the lead pin ( 16 a) through the lead pin ( 16 f). An overcurrent limiting means ( 20 ) is provided, which can suppress overcurrent flowing into the thermo-module ( 5 ) in its heating direction. The overcurrent limiting circuit ( 20 ) is provided with a bypass line ( 21 ), a resistor ( 22 ), and a diode ( 23 ). When a current flows in the heating direction, the diode ( 23 ) is turned on, whereby the current is shunted to the thermo-module ( 5 ) and bypass line ( 21 ) for flow, and accordingly, the overcurrent flowing into the thermo-module ( 5 ) can be effectively suppressed.