An atomic oscillator includes a semiconductor laser housed in a container, an atom cell housing alkali metal atoms and irradiated with a light output from the semiconductor laser, a light receiving element that detects an intensity of the light transmitted through the atom cell and outputs a detection signal, a temperature sensor housed in the container, a first temperature control element housed in the container and controlled based on output of the temperature sensor, and a second temperature control element housed in the container and controlled based on the detection signal. A distance between the second temperature control element and the semiconductor laser is smaller than a distance between the first temperature control element and the semiconductor laser.