A main controller used in a security system having a sensor or a camera performs wireless communication with the sensor or the camera so as to control the sensor or the camera. The main controller has a plurality of communication sections that perform wireless communication by using communication systems having different communication speeds. The camera transmits and receives information by performing wireless communication with the main controller. The camera is provided with a first camera communication section and a second camera communication section that perform wireless communication by using communication systems having different communication speeds, and a camera communication control section for selecting the first camera communication section and the second camera communication section according to the information to be transmitted and received, as a communication section to perform communication.