An atomic oscillator is disclosed, including an Alkaline metal cell, a light source illuminating a laser beam to the Alkaline metal cell, and a light detector detecting light passing through the Alkaline metal cell. The Alkaline metal cell includes a first member, a second member, a cell internal portion, and an Alkaline metal raw material. In the first member, a first glass substrate is bonded on a second surface of a first substrate where a first opening part is formed. In the second member, a second glass substrate is bonded to a fourth surface of a second substrate where a second opening part is formed. The cell internal portion is formed by the first opening part and the second opening part by bonding the first surface to the third surface. The Alkaline metal raw material is enclosed by the cell internal portion.