A piezo-electric acceleration sensor, including: a piezo-electric polymer membrane element having an element through-hole; a diaphragm having a diaphragm through-hole and attached to the piezo-electric membrane element so that the diaphragm hole is concentric to the element through-hole to form a laminate with a laminate through-hole; and a fixing mechanism, having a sensing hole, for fixing the laminate in a stretched manner, and wherein: the laminate through-hole has about 2.25 to about 80% of the area of the sensing hole; and the diaphragm and the piezo-electric element meet the equation: (Eb×Tb.sup.3)/(Ep×Tp.sub.3)≧about 5 wherein Eb, Tb, Ep and Tp are Young's modulus thickness of the diaphragm, Young's modulus, and thickness of the piezo-electric element, respectively, whereby acceleration, applied to the diaphragm, is detected based on a quantity of electricity generated due to strains in a piezo-electric element.