A radio device for transmitting or receiving desired information through an MIMO transmission line, and an electronic device and an imaging device which have the radio device and supplied with drive power together with the radio device may realize to implement a desired radio transmission flexibly in the form suitable for the battery residual amount and power consumption, in which plural antenna sections for performing radio communication by a spatial division multiplexing method on an MIMO transmission line, and a controller for increasing or decreasing the number of the antenna portions used for the radio transmission.