An equalizing filter circuit includes a first transmission line in which a plurality of first delay devices 104a are connected in cascade to input terminal 101, a second transmission line in which a plurality of second delay devices 107a are connected in cascade to output terminal 102, a plurality of weighting circuits 105a connected in parallel between the first transmission line and the second transmission line and having a gain which is adjustable by setting coefficients, and variable adjusting circuit 108a arranged at the output side of at least one of weighting circuits 105a for correcting a fluctuation of the output characteristics of the weighting circuits.