Provided is communication apparatus and method using a transmission medium, in an environment where at least one transmitter and at least one receiver are connected to at least one human body which is a conductive transmission medium, in which the receiver requiring any information data requests a transmission to the transmitter or the transmitter sends a signal indicative of a transmission of required information data, and then, the transmitter provides the required information data to the receiver requiring the corresponding information data, thereby providing a communication environment without interference between the transmission means and the receiving means.