Abstract: A radio paging receiver having a primary power source, and outputs boosted by DC--DC converters as its secondary power sources. The radio paging receiver is provided with a first DC--DC converter which operates all the time or while the power source is on and a second DC--DC converter which operates intermittently to be active only when the load current is greater. The first DC--DC converter is so set as to be higher in source efficiency under light load and the second, as to normally operate even under heavy load. The first DC--DC converter supplies power to the circuits including a decoder in all the modes including the standby mode and the battery saving mode, both imposing only a light load. The second DC--DC converter intermittently operates to be active only in the heavy-load message data processing and message display modes, and supplies power to a CPU and an LCD signal processor in these modes.