A laser frequency stabilizer configured to irradiate laser light on an absorption cell to obtain a light output signal and, based on a saturated absorption line contained in the light output signal, change a resonator length to stabilize an oscillation frequency of the laser light to a specific saturated absorption line, the laser frequency stabilizer comprising: a converter configured to convert the laser light that passes through the absorption cell into the light output signal, an actuator configured to change the resonator length, and a controller configured to control operation of the actuator, the controller comprising: a signal analyzer configured to analyze the light output signal converted by the conversion mechanism; and a stabilization determiner configured to determine whether the light output signal is stabilized, based on an analysis result from the signal analyzer, a memory; said laser frequency stabilizer being characterized in that: said signal analyzer is configured to store output values of the light output signal obtained at predetermined sampling intervals over a fixed amount of time in the memory in order and read the output values of the light output signal from the memory after the fixed amount of time has elapsed; said stabilization determiner is configured to compare the output values of the light output signal (S 1) or a standard deviation of the output values of the light output signal (S 1) with a predetermined threshold value, wherein if the output values of the light output signal or the standard deviation of the output values of the light output signal is less than the threshold value, the stabilization determiner determines that the light output value is stabilized. a converter configured to convert the laser light that passes through the absorption cell into the light output signal, an actuator configured to change the resonator length, and a controller configured to control operation of the actuator, the controller comprising: a signal analyzer configured to analyze the light output signal converted by the conversion mechanism; and a stabilization determiner configured to determine whether the light output signal is stabilized, based on an analysis result from the signal analyzer, a memory; a signal analyzer configured to analyze the light output signal converted by the conversion mechanism; and a stabilization determiner configured to determine whether the light output signal is stabilized, based on an analysis result from the signal analyzer, a memory; said signal analyzer is configured to store output values of the light output signal obtained at predetermined sampling intervals over a fixed amount of time in the memory in order and read the output values of the light output signal from the memory after the fixed amount of time has elapsed; said stabilization determiner is configured to compare the output values of the light output signal (S 1) or a standard deviation of the output values of the light output signal (S 1) with a predetermined threshold value, wherein if the output values of the light output signal or the standard deviation of the output values of the light output signal is less than the threshold value, the stabilization determiner determines that the light output value is stabilized.