Power required for a printing operation can be supplied while supplying power to a connected external device. A printer 1 connects to a smart device 2, and has: a power circuit 14; a USB interface 15 capable of supplying power to the smart device while communicating by wire with the smart device 2; a print unit 16 that prints; and a controller 11 that controls the print unit 16 to print in a power conservation mode when information instructing printing by the print unit 16 is received by the interface 15 from the smart device 2 while supplying power from the power circuit 14 to the smart device 2.