PURPOSE: To provide an input circuit, for a body-movement detection apparatus, by which a slow walking operation up to a running operation can be detected in a comparatively short processing time.

CONSTITUTION: In a body-movement detection apparatus, a signal Vi from an accelerometer 1 is input to a comparison circuit 2, the resistance connection of ladder resistance 3 is changed over by signals from output ports R00 to R04 at a CPU 4, threshold voltages to be applied to the comparison circuit 2 are changed over sequentially, and the input signal Vi is A/D-converted. In the body-movement detection apparatus, the threshold voltages to be applied to the comparison circuit 2 by the ladder resistances 3 are changed over nonlinearly so as to be applied.