To extend the frequency characteristic by cancelling the input parasitic capacitance at an input terminal of an preamplifier for an HDD device.

The positive side of an amplifier circuit 10 constituting a circuit for cancelling the input parasitic capacitance is connected to a line for connecting the input terminal 4 and one of differential inputs of an ideal reproduction amplifier circuit 6, and the negative side is connected to another one of the differential inputs of the ideal reproduction amplifier 6, then, a capacitance 15 for cancelling the input parasitic capacitance 5 is connected between the output of the amplifier circuit 10 constituting the circuit for cancelling the input parasitic capacitance 5 and the line for connecting one of the differential inputs of the ideal reproduction amplifier circuit 6 with the input terminal 4.