To obtain a new interfering quantity measuring method by temporarily transmitting a space frame without including information and measuring energy at the time of its receiving to simply detect an unnecessary wave signal existing in a sector band.

For example, a frame No. (n+1) is turned to be a space frame in an incoming signal to a base station from a mobile station and a frame No. (n+2) is turned to be a space frame in an outgoing signal to the mobile station from the base station. Then the transmission and reception of a normal radio frame is executed and when the number of the frame becomes a first frame number fixed as an incoming space frame, the mobile station stops the normal radio frame to transmit the space frame. The base station recognizes the received signal as the space frame and measures the energy of the received signal to detect unnecessary waves excepting for a user signal. In addition, the interfering quantity is measured from a primary modulation wave inverse- spread by each user signal to grasp the interfering quantity of the unnecessary waves at the time of the space frame, namely incoming.