One embodiment provides a power supply device for supplying power to a medical device main body implanted in a human body. The power supply device includes a power supply coil configured to supply power wirelessly to a power reception coil provided in the medical device main body from outside the human body through electromagnetic induction. And, the power supply coil includes: a cylindrical coil formed by winding a lead wire helically; and a ring-shaped member made of a magnetic material and is disposed so as to surround an outer circumference of the cylindrical coil.