A laser light adjusting method includes detecting a pair of mode hops and a comparison saturated absorption line group of the pair of mode hops based on an intensity of a light output signal in response to a change applied to an actuator, comparing a mode center voltage value with a comparison voltage value which is the voltage value at which the comparison saturated absorption line group was generated; a control temperature adjustment process that increases a control temperature when the comparison voltage value is lower than the mode center voltage value, and that decreases the control temperature of the temperature adjuster when the comparison voltage value is greater than the mode center voltage value; and a laser light stabilization step that stabilizes an emission frequency of the laser light to a specific saturated absorption line after the control temperature adjustment process.