A printing device that and a control method of the printing device enable supplying power to a connected external device without affecting operation of the printing device. A thermal printer 1 has a USB connector 15 that connects to a smart device 2; a power supply circuit 14; a print mechanism 17 that operates using power supplied from the power supply circuit 14; a communicator 16 that communicates with the smart device 2; and a controller 11 that receives a command to start or stop operation of the print mechanism 17 from the smart device 2 through the communicator 16, and controls the power supply to the smart device 2 from the power supply circuit 14 according to the timing when operation of the print mechanism 17 starts and stops.