A data transmission system using a human body as a signal transmission path includes a transmitter and a receiver. The transmitter uses a pair of electrodes which are held in close proximity to the skin of the human body. The transmitter transmits data to the receiver through the signal transmission path partly extending through the human body when a user carrying the transmitter touches a touch electrode of the receiver. The electrodes are integrated into a garment worn by the user in such a manner that the electrodes are kept in a closely facing relation to the skin of the user, thereby establishing the electrical path extending through the human body. With the integration of the two electrodes into the garment, the user wearing the garment as an everyday clothes or uniform can be easy and convenient to carry the transmitter for successful transmission of the data.