A signal separator for separating multiple signals contained in a received signal from each other based on a replica of the received signal, comprising: a sampling unit configured to sample the received signal at prescribed sampling timings in each unit time period; an index output unit configured to monitor sampling counts (n 1) received from the sampling unit and output an index signal including indexes designating groups of samples of the received signal, wherein the index output unit obtains each of the indexes (n 3) by calculating a remainder of dividing a sampling count at the corresponding sampling timing by the number of sampling timings in the unit time period in a way that the sampled signals are grouped into multiple categories based on said indexes (n 2), such that the sampled signals grouped in the same category have similar signal characteristics according to the sampling timing: a coefficient-variable filter (16, 17) configured to generate and output the replica of the received signal for each group of samples based on a channel estimation value and a signal point candidate, at least one of the channel estimation value and the signal point candidate being generated according to the index signal; a subtractor configured to subtract the replica from the sampled signal and output a subtraction result as a residual signal; and a maximum likelihood sequence estimator configured to estimate a sequence for each of the multiple signals based on the residual signal, taking into account signal state transition, and output the estimation result at a signal output timing determined by the index signal. a sampling unit configured to sample the received signal at prescribed sampling timings in each unit time period; an index output unit configured to monitor sampling counts (n 1) received from the sampling unit and output an index signal including indexes designating groups of samples of the received signal, wherein the index output unit obtains each of the indexes (n 3) by calculating a remainder of dividing a sampling count at the corresponding sampling timing by the number of sampling timings in the unit time period in a way that the sampled signals are grouped into multiple categories based on said indexes (n 2), such that the sampled signals grouped in the same category have similar signal characteristics according to the sampling timing: a coefficient-variable filter (16, 17) configured to generate and output the replica of the received signal for each group of samples based on a channel estimation value and a signal point candidate, at least one of the channel estimation value and the signal point candidate being generated according to the index signal; a subtractor configured to subtract the replica from the sampled signal and output a subtraction result as a residual signal; and a maximum likelihood sequence estimator configured to estimate a sequence for each of the multiple signals based on the residual signal, taking into account signal state transition, and output the estimation result at a signal output timing determined by the index signal. a coefficient-variable filter (16, 17) configured to generate and output the replica of the received signal for each group of samples based on a channel estimation value and a signal point candidate, at least one of the channel estimation value and the signal point candidate being generated according to the index signal; a subtractor configured to subtract the replica from the sampled signal and output a subtraction result as a residual signal; and a maximum likelihood sequence estimator configured to estimate a sequence for each of the multiple signals based on the residual signal, taking into account signal state transition, and output the estimation result at a signal output timing determined by the index signal.