A method and apparatus capable of restricting the resending operation are disclosed, in which the resending operation is controlled by determining the conditions of the input signal from a movable transmitting end, based on the guard interval period set in the signal to be resent, thereby resending only a valid transmission signal. Once an input signal is supplied from the movable transmitting end to the resending apparatus, a guard information detector determines whether the input signal is to be resent or not, based on the degree of correlation of the guard interval period, and controls the operation of a voltage-controlled amplifier, thereby resending only a valid transmission signal. This determination is made based on the degree of correlation between a signal converted from the input signal and the guard interval period of the signal delayed from the converted signal.