A partial response transmission system in which a data signal is transmitted from a transmission side to a reception side through a transmission medium, includes an equalizing circuit provided in the transmission side or the reception side, and configured to adjust a transfer function for an entire system including the transmission medium to a desired transfer function by delaying input data over a plurality of states in units of a period equal to a transition time of a single bit response by the desired transfer function of a partial response transmission and by weighing and adding data in the plurality of stages; and a deciding circuit provided in the reception side and configured to decide an output data from a signal received through the transmission medium through processing under consideration of the desired transfer function.