A load detection device includes a piezoelectric body unit adapted to be deformed by receiving an electric voltage, the piezoelectric body unit generating an electric charge by receiving an external load, a drive portion applying the electric voltage to the piezoelectric body unit for vibrating thereof, a detection portion detecting the electric charge generated at the piezoelectric body unit, and an adjusting member adjusting a pressure applied to at least one pressure sensing surface provided at the piezoelectric body unit to restrain the vibration of the piezoelectric body unit.