The acceleration applied to a selected device such as a magnetic disc drive system can be detected by the use of an acceleration detector having at least one piezoelectric acceleration sensor unit. The sensor unit includes a piezoelectric element, a supporting member for the piezoelectric element and two electrical leads. The piezoelectric element is formed with a pair of elongate sheets made of a piezoelectric ceramic and an intermediate insulation layer interposed between the elongate sheets to generate a voltage difference instantaneously therebetween in response to the acceleration of the acceleration detector. The support member is made of an electrically insulating resin, and has a concave which is formed with side and bottom walls and a top opening. The side wall is provided with a slit in which the piezoelectric element is tightly caught in such a manner as to divide the concave into two open-chambers and be supported by the support member in a cantilever fashion. The electrical leads extend into the concave to make electrical connections between the elongate sheets and the electrical leads. In the present invention, since the piezoelectric element can be attached accurately at a predetermined direction to the supporting member by forcing it into the slit, it is possible to stably supply the acceleration detector having excellent sensitivity to the acceleration without causing variations in detecting direction of the acceleration. <IMAGE>
