A frequency-stabilized laser device comprises an actuator (25) arranged to vary the cavity length; an actuator driver (44) arranged to apply a voltage to the actuator for changing displacement; a temperature detector (51) arranged to detect the temperature (53) on the cavity; a temperature adjuster arranged to heat or cool the cavity; a cavity temperature controller (54) arranged to control the temperature adjuster based on a previously given instruction temperature and the temperature on the cavity detected at the temperature detector; and an instruction temperature corrector arranged to correct the instruction temperature given to the cavity temperature controller such that the voltage applied to the actuator remains almost constant.