A wireless power supply device comprising: a wireless power transmission circuit comprising a transmission coil ; and one or more processors (480;620) which are functionally connected with the wireless power transmission circuit, wherein the one or more processors are configured to: based on a power provided from a power supply device , control the wireless power transmission circuit to generate (1401,1405;1605;1709) a first power to wirelessly charge a wireless power reception device by providing a first charging voltage to the transmission coil, transmit (1405;1605;1709), through the wireless power transmission circuit, to the wireless power reception device, information indicating a second charging voltage that is supportable by the wireless power supply device , after the transmitting of the information, receive (1411; 1607; 1711), from the wireless power reception device, a power change request signal through the wireless power transmission circuit, and in response to receiving the power change request signal, control the wireless power transmission circuit to generate (1421;1611;1719) a second power to wirelessly charge the wireless power reception device by providing the second charging voltage to the transmission coil. a wireless power transmission circuit comprising a transmission coil ; and one or more processors (480;620) which are functionally connected with the wireless power transmission circuit, wherein the one or more processors are configured to: based on a power provided from a power supply device , control the wireless power transmission circuit to generate (1401,1405;1605;1709) a first power to wirelessly charge a wireless power reception device by providing a first charging voltage to the transmission coil, transmit (1405;1605;1709), through the wireless power transmission circuit, to the wireless power reception device, information indicating a second charging voltage that is supportable by the wireless power supply device , after the transmitting of the information, receive (1411; 1607; 1711), from the wireless power reception device, a power change request signal through the wireless power transmission circuit, and in response to receiving the power change request signal, control the wireless power transmission circuit to generate (1421;1611;1719) a second power to wirelessly charge the wireless power reception device by providing the second charging voltage to the transmission coil. based on a power provided from a power supply device , control the wireless power transmission circuit to generate (1401,1405;1605;1709) a first power to wirelessly charge a wireless power reception device by providing a first charging voltage to the transmission coil, transmit (1405;1605;1709), through the wireless power transmission circuit, to the wireless power reception device, information indicating a second charging voltage that is supportable by the wireless power supply device , after the transmitting of the information, receive (1411; 1607; 1711), from the wireless power reception device, a power change request signal through the wireless power transmission circuit, and in response to receiving the power change request signal, control the wireless power transmission circuit to generate (1421;1611;1719) a second power to wirelessly charge the wireless power reception device by providing the second charging voltage to the transmission coil. <EOS>