To provide an acceleration sensor capable of improving the yield by preventing assembling failures, caused by sealing of internal space in a case that is covered by an acceleration detector using adhesive.

In the acceleration sensor, a support section 23 of a diaphragm 20 constituting the acceleration detector 2 is bonded to the inner wall surface 52a of a case 5 by adhesive 4, and the internal space 3 covered by the acceleration detector 2 is formed in the case 5. A degassing groove 58, communicating with the outside from the internal space 3, is formed in the inner surface of the case at the furthest position from the bonding surface by the adhesive 4, gas going attempting expand in the internal space 3 is evacuated from the degassing groove 58, and the floating of the acceleration detector 2 is prevented. Adhesive reserving grooves 59 are formed on both sides of the degassing groove 58 so as to prevent the adhesive 4 from flowing into the degassing groove 58.