The present invention relates to power supplies, and more particularly, to a power supply having a maximum power point tracking function that can reduce manufacturing costs and circuit size by using a maximum power point tracking section with a simplified circuit in a solar photovoltaic power generator supplying power using sunlight instead of using a micro controller, the maximum power point tracking section that controls power switching according to a result of integration of a value obtained by dividing a power variation by a voltage variation to track a maximum power value. A power supply having a maximum power point tracking function according to an aspect of the invention may include: a converter section switching input power, and converting the switched input power into predetermined DC power; and a maximum power point tracking section detecting a voltage and a power value of the input power, dividing a variation of the detected power by a variation of the detected voltage, integrating a result of the division, and controlling the switching operation of the converter section according to a value of the integration.