An imaging apparatus is provided. The apparatus includes a sound collecting unit configured to collect speech in a monitored environment, a shooting unit configured to shoot video in the monitored environment, a detection unit configured to detect a change in a state of the monitored environment based upon a change in data acquired by the sound collecting unit, the shooting unit and a sensor for measuring the state of the monitored environment, a recognition unit configured to recognize the change in state with regard to speech data acquired by the sound collecting unit and video data acquired by the shooting unit, and a control unit configured to start up the recognition unit and select a recognition database, which is used by the recognition unit, based upon result of detection by the detection unit.