PURPOSE: To improve the sensitivity of a beeper without remodeling the beeper body by receiving a signal from a transmitting station, amplifying the received signal, sending the amplified signal to the beeper, and operating the beeper.

CONSTITUTION: The signal sent from a transmitting antenna 2 of a transmitting means of a transmitting station 1 by a radio wave 3 is received by a receiving antenna 5 of the receiving means of a reception sensitivity improving device 4, an the weak signal is amplified by an amplifier 6 of an amplifying means. The signal amplified by the amplifier 6 is sent to a transmitting antenna 8 of the transmitting means of the improving device 4 and sent from the transmitting antenna 8 to a receiving antenna 11 of the receiving means of a beeper 10 by a radio wave 9. The beeper 10 receives the above-mentioned signal and is made into an operating state. The above-mentioned improving device 4 has a container body 12 to house the beeper 10, the receiving antenna 5 is provided for its back face 13, the transmitting antenna 8, the amplifier 6, and a battery 7 are incorporated in the body 12, and the battery 7 can be taken in and out from the part of a cover 14 of the body.