A heat conversion device according to an embodiment of the present invention comprises: a plurality of P-type thermoelectric legs and a plurality of N-type thermoelectric legs which are electrically connected and arranged in an array; an insulating part disposed on one surface of the plurality of P-type thermoelectric legs and the plurality of N-type thermoelectric legs; a heat sink disposed on the insulating part; a fan disposed spaced a predetermined distance from the heat sink; and a plurality of fastening members having moduli of elasticity of 1*103 kgf/cm2 to 30*103 kgf/cm2 and fixing the heat sink and the fan. Each one of the fastening members comprises: a shaft part; a first fixed part which is disposed at one end of the shaft part and fixed to the heat sink; a second fixed part which protrudes from an outer circumferential surface of the shaft part and is fixed to the fan; and a separating part which protrudes from the outer circumferential surface of the shaft part and is disposed between the heat sink and the fan to separate the heat sink and the fan, wherein the width of the second fixed part increases toward the first fixed part, and the shaft part, the first fixed part, the second fixed part, and the separating part are integrally formed.