A wireless power transmitter is provided. The wireless power transmitter includes a power supply unit that supplies Alternating Current (AC) power having a predetermined voltage value, a rectification unit that is connected to the power supply unit, and rectifies the AC power, a voltage adjustment unit that is connected to the rectification unit, and adjusts a magnitude of an output voltage value of the rectified power, and outputs the adjusted power to a power transmission unit, the power transmission unit that generates the adjusted power output from the voltage adjustment unit as a signal in a form in which wireless power transmission is possible, and transmits the generated signal to a wireless power receiver, and a control unit that controls the magnitude of the output voltage value of the rectified power to be adjusted by the voltage adjustment unit in accordance with a predetermined criterion.