Collision detecting sensor for a vehicle

Collision detecting sensor for detecting a collision of a vehicle bumper (2) with an object, wherein the collision detecting sensor comprising: an absorber (6, 16) which is configured so that it is deformed in the collision to absorb the impact force of the collision, wherein the absorber (6, 16) in the bumper (2) is located and (in front of a bumper reinforcement member 4) is located in a vehicle front-rear direction; a chamber member (7, 17) having a chamber space (7a, 17a) defining therein, said chamber portion (7, 17) in the bumper (2) is situated and in front of the bumper reinforcement member (4) in the vehicle front- rear direction is situated; a pressure sensor (8) which is adapted to detect the pressure in the chamber space (17a 7a); and a collision detecting means (9) for detecting the collision based on the detected pressure, wherein a front end (6b, 16b) of the absorber (6, 16) further from the bumper reinforcement member (4) as a front end (7b, 17b) located the chamber part (7, 17) located in the vehicle front-rear direction is said chamber portion (7) outside the absorber (6) is positioned, said chamber member (7) does not overlap the absorber (6) in the vehicle front-rear direction, and the absorber (6) and the chamber part (7) are separate components, wherein a rear end of the absorber (6) which is located opposite the front end of the absorber (6) in the vehicle front-rear direction on a front surface (4a) of the bumper reinforcement member (4) is fixed, and a rear end of the chamber portion (7) which is located opposite the front end of the chamber part (7) in the vehicle front-rear direction on a front surface (4a) of the bumper reinforcement member (4) is fixed, and wherein the rear end of the absorber (6) and the rear end of the chamber part (7) on the front surface (4a) of the same bumper reinforcement member (4) is fixed.