A vehicle includes a first detector configured to transmit and receive an ultrasonic signal to detect a presence or absence of an occupant inside the vehicle based on the ultrasonic signal; a second detector configured to detect an opening and closing state of a window including at least one of an upper window or a side window provided in the vehicle; and a controller configured to compare an intensity of the ultrasonic signal received by the first detector and a preset level to determine the presence of the occupant. The controller may be configured to change the preset level based on the opening and closing state detected by the second detector.