To provide an "in-vehicle machine and a connection destination switching method in the in-vehicle machine" for performing communication with only one of a plurality of opposite communication devices (cellular phone and camera or the like) without a pairing operation by merely providing one radio communication part.

The in-vehicle machine includes: a telephone function of connecting a cellular phone to perform telephone communication through the radio communication part of the in-vehicle machine; and a display function of photographing the back scenery of a vehicle to display the photographed back scenery on a display device. In the in-vehicle machine, the radio part of a camera for photographing the back scenery of the vehicle and the radio part of the cellular phone are beforehand registered into the radio communication part of the in-vehicle machine as a pairing destination, respectively, communication is made to be possible only with the radio part of the camera in a state that the vehicle is put in reverse, and the communication is made to be possible only with the radio part of the cellular phone in a state that a gear is shifted in a position other than a back gear.