An apparatus configured to count people in a target area includes a wireless transceiver and a controller. The wireless transceiver is configured to radiate an impulse electromagnetic wave to the target area and receive a reflection signal from the target area, and the controller is configured to obtain a signal strength of the reflection signal over a reception time period during which the reflection signal is received and count people according to the signal strength, considering that the signal strength is weakened in proportion to the reception time period.