According to the disclosure of the present invention, a method of a Network Body Area Network (MBAN) master to control the channel defaulting of an MBAN terminal in an MBAN system is provided. The method includes: performing an association process with the MBAN terminal through a channel of a first frequency band; and transmitting control information for the channel initialization of the MBAN terminal to the MBAN terminal. The control information includes a channel defaulting timer, and a value of the channel defaulting timer indicates a time between the timing when the MBAN terminal cannot receive a signal from a channel of the first frequency band in use and the timing when the channel search of a second frequency band starts.