Abstract: [Problem] To provide an atomic frequency obtaining device which enables an improvement in mass-productivity and a reduction in size, and an atomic clock which uses the atomic frequency obtaining device. [Solution] A laser light source 20, a vapor cell unit 30 that includes a vapor cell 31 in which atomic gas was enclosed, and a light detector 40 are provided on a circuit board 10. Light emitted from the laser light source 20 is reflected by a first reflective member 51 so that the direction in which the light travels is changed and the light passes through the vapor cell. The light passes through the vapor cell 31, and is reflected by a second reflective member 52 so that the direction in which the light travels is changed and the light travels toward the light detector 40.