A knocking sensor including: a sensor body including, a metal shell including a tubular portion and a flange portion, a piezoelectric element, a weight sandwiching the piezoelectric element with the flange portion, a flange portion-side electrode plate placed between the piezoelectric element and the flange portion, a weight-side electrode plate placed between the piezoelectric element and the weight, a flange portion-side insulating plate placed between the flange portion and the flange portion-side electrode plate, and a weight-side insulating plate placed between the weight and the weight-side electrode plate; and a resin molded body made of a resin and covering the sensor body, wherein the resin molded body is made of polyphenylene sulfide, and wherein the flange portion-side insulating plate and the weight-side insulating plate are made of a resin that does not contain ester bond.