An atomic oscillator includes an atomic cell in which alkali metal atoms are encapsulated, a light source section configured to receive the supply of a bias and emit light including a resonance light pair for causing the alkali metal atoms to resonate, a temperature adjusting element configured to adjust the temperature of the light source section, a bias detecting section configured to detect information concerning the bias, and a light-source-temperature control section configured to control the temperature adjusting element using the information detected by the bias detecting section.