Abstract: A device power supply system is applied to a building including a recessed space that is formed to be recessed with respect to a wall surface of a living space and is opened toward the living space and is for supplying electric power to a device, and the device power supply system includes: a device arrangement portion that is provided in the recessed space and in which the device is to be disposed; and a power transmitter configured to transmit electric power to be supplied to the device disposed in the device arrangement portion as microwaves, and the power transmitter is disposed on a peripheral portion of the recessed space or at an inner side of the peripheral portion, and a transmission direction of the microwaves is set to a direction intersecting a depth direction of the recessed space.