In the wireless communication base station sharing apparatus, a first signal combiner/distributor is connected to a main system duplexer through a first port, distributes a signal received through the first port to second and third ports, combines the signals received through the second and third ports according to the phases of the signals, and provides the combined signal through the first port or a fourth port. A second signal combiner/distributor is connected to a subsystem duplexer through a fifth port and the antenna through an eighth port, distributes a signal received through the fifth port to sixth and seventh ports, combines the signals received through the sixth and seventh ports according to the phases of the signals, and provides the combined signal through the fifth or eighth port. Variable filters are provided in signal paths between the first and second signal combiner/distributors.