PURPOSE: To obtain an economic device which does not require much space by providing a radiation measured value of every radiation detector from a radiation detection signal sorted by pulse height through a pulse height sorting method.

CONSTITUTION: Control input pulses SRi outputted successively by pulse output circuits 27 of respective preamplifier circuits 3 are multiplexed and transmitted in order while having their pulse height. A radiation detection output pulse SOi which is multiplexed as mentioned above and supplied to the pulse height discriminating circuit 13 of the measuring instrument 11 through a cable 9-1 while having different pulse height is passed through the pulse height discriminating circuit 13 to remove noises, etc., and then supplied to a pulse height sorting circuit 15, which sorts pulses by pulse height, i.e. radiation detectors. Consequently, the number of cables and wiring construction between the radiation detectors and measuring means are reduced to realize economic constitution and save the wiring space.