Device for converting sound using piezoelectric driving body

A device for converting sound comprises: a main piezoelectric driving body; a vibration plate which is physically coupled to the main piezoelectric driving body; a support portion for supporting the main piezoelectric driving body and/or the vibration plate, from one fixed point that is positioned to be on the inside space of an outer circumference of the main piezoelectric driving body; a housing for accommodating the main piezoelectric driving body and the vibration plate; and an amplification portion, which is interposed between the support portion and the housing, for increasing the movement of the support portion by responding to the operation of the main piezoelectric driving body, wherein the main piezoelectric driving body and the outer circumference of the vibration plate vibrate freely with the fixed point at the center.