To provide a voice input signal correction device in which a speech sensitivity during driving is improved and the quality of a speakerphone is improved by placing a microphone to both front and rear sides of a driver's seat in the inside of a vehicle respectively and amplifying each output signal from the microphones by using a differential amplifier while eliminating only noise.

This voice input signal correction device provides an automobile portable telephone set with a signal correction means 400, consisting of a 1st microphone 410 placed to a front side and an upper part of a driver's seat, a 2nd microphone 420 placed to a rear side of the driver's seat and a differential amplifier 430 comparing voice signals inputted through the microphones to amplify only a necessary component to a prescribed level, to cancel noise in the vehicle and to output a correction signal.