An FM transmitter which can be easily connected to an existing computer or the like and does not need any troublesome operation is provided. An FM transmitter 100 has an USB device function which can be connected to a PC 400 as an USB host device and comprises a power supply circuit 130 which is connected to the power supply pin of an USB socket 410 to generate a predetermined operating voltage when an USB plug 110 is connected to the USB socket 410 of the PC 400, an USB controller 120 for requesting that its own apparatus being a device audio source inputs/outputs data by isochronous transfer in a configuration performed by the PC 400 and a transmission processing section 140 which is actuated by the operating voltage supplied by the power supply circuit 130 and applies FM-modulation to audio data outputted from the PC 400 via the USB socket 410 for transmission.