A chopper amplifier suitable for biological signal processing in a time division manner which amplifies a plurality of input signals is proposed. Since biological signals are very low frequency signals, a chopper amplifier which has low 1/f noise is used. Furthermore, the amplifier has a highpass characteristic in order to remove the DC voltage contained in the signals obtained from the sensor. A method to remove the DC voltage accurately and quickly using DC voltage holding capacitors and voltage buffers is proposed. HSPICE simulation results show that the proposed 4-input circuit reduces the chip area by 26% and the power consumption by 29% compared to the conventional circuit.