Abstract: An acceleration detector comprising a housing adapted to be rigidly secured to an object of which acceleration is to be detected and a transducer assembly disposed within the housing for detecting the acceleration on the housing. The transducer assembly comprises a disc-shaped diaphragm having a circular central region flexible in response to the acceleration on the housing and a plurality of radial arms integrally extending at equal intervals from the central region and supported by the housing at outer ends. A disc-shaped piezoelectric element is attached to the central region of the diaphragm for sensing flexture of the central region and generating a signal representative of the acceleration on the housing. The central region has a diameter not smaller than that of the piezoelectric element. The radial arms may have a total circumferential width dimension effective to improve temperature vs. resonance frequency characteristics of the transducer assembly.