Abstract: A feedback type comb filter comprises a first delay circuit supplied with an input signal, a first adding circuit supplied with an output of the first delay circuit, a second delay circuit supplied with an output of the first adding circuit, a second adding circuit supplied with an output of the second delay circuit and the input signal which is passed through a signal path having a delay time .tau..sub.3, and a feedback path including a coefficient multiplier for multiplying a coefficient k to an output of the second adding circuit. The feedback path has a delay time .tau..sub.2 and supplies the output of the second adding circuit to the first adding circuit through the coefficient multiplier. The first adding circuit adds the output of the first delay circuit and the signal from the feedback path, and supplies the output thereof to the second delay circuit. A delay time .tau..sub.1 of the first delay circuit is equal to a sum of the delay time .tau..sub.2 of the feedback path and the delay time .tau..sub.