To provide a pressure sensor, a pressure gauge, and an electronic apparatus which have high accuracy, high reliability, and especially high moisture resistance without pressure sensitivity changing according to the change in environmental conditions.

A pressure sensor 10 includes: a pressure sensitive element 40; a supporting member 30 to which the pressure sensitive element 40 is fixed; and bellows each of which has an opening part on one end and a through port on the other end. Adhesive joints 70 between the bellows and the supporting member 30 are side faces of the bellows, which are parallel in a displacement direction of the bellows.