The present invention relates to a radio resource reallocation method based on the circuit mode. In order to efficiently use the radio resource in the packet-based data transmission system, a circuit mode radio resource is reallocated based on a rearrangement information element and a rearrangement counter information element by using the circuit mode. Accordingly, an unused region of the discontinuous radio resource that can be generated by resource de-allocation and resource change can be eliminated, and a resource allocation mismatch that can be generated by a MAP receiving error can be solved.