Provided is an apparatus and method for estimating inverse channel of a repeater's receiving channel, which ensures stability and causality by generating a time-domain filter coefficient having information on an inverse channel of repeater's receiving channel from a signal transmitted from a main transmitter or another repeater. The apparatus includes: a channel estimator for estimating a channel established by a transmission path from a received signal; an inverse minimum phase filter coefficient generator for generating inverse channel of a minimum phase channel from the estimated channel, and converting the inverse channel of the minimum phase channel into a time-domain filter coefficient; an inverse group delay filter coefficient generator for generating a time-domain filter coefficient by using the estimated channel and the minimum phase channel; and a combiner for generating an inverse channel of a receiving channel in a time domain by combining the filter coefficient and the filter coefficient.