The present invention relates to a human body sensing apparatus with improved accuracy, in which whether a moving direction of a human body is a ‘determinate entry or exit’ or an ‘indeterminate entry or exit’ is determined by analyzing a sensing signal outputted from each of sensor units, and room occupancy states are classified into a ‘ZERO’ state, a ‘CHECK’ state, a ‘WAIT’ state, an ‘AOL’ state and an ‘IOL’ state depending on a determined result. Even a variety of unexpected behaviors that a human can perform in a sensing area of the sensor units can be detected, and thus correctness and correction rate are superior in calculating the number of people staying in a room.