In a transmission unit 1 used in a wireless video transmission system 10 in which a medical image is transmitted and received by radio communication, a transmission I/F 13 is capable of performing radio communication with a plurality of receivers 3 connected to a plurality of monitors 2. A control unit 17 acquires an identifier for identifying a receiver 3 connected to a selected single monitor 2 when an instruction is received to select one monitor 2 on which the medical image is to be displayed from among the monitors 2, and controls the transmission I/F 13 such that the identifier will be used when the medical image is transmitted.
