Abstract: A heating apparatus for hyperthermia utilizes electromagnetic waves for locally heating cancerous cells within a living body. Electromagnetic waves output from a single electromagnetic wave generating device are branched into a plurality of electromagnetic wave outputs, which are respective employed to conduct hyperthermia treatments for a plurality of patients, the level of each of the branched outputs being adjustable. The whole of the hyperthermia system is controlled in a concentrated fashion from a single section by way of time-division multiplexing. It is therefore possible for a plurality of patients to be subjected to hyperthermia treatment at the same time and in parallel with each other, even when the conditions of these patients differ from one another. Further, it is advantageously possible to simplify the arrangement of the system as a whole and provide an even more precise control of the system.