When it judges, that the judgment section which judges whether or not it possesses the multiple reception antennas, the calculation section which calculates the difference value of the signal strength which is obtained from the antenna and the multiple reception antennas which for acquisition acquire the information from the capsule die endoscope cyclically and the signal strength which is obtained from the previous multiple reception antennas (62) with, comparing with difference value and threshold, it presumes the information of position, (63) with, the judgment section (63) presumes the information of position the position information presumption section which presumes the information of position of the capsule die endoscope (64) with, it had.複数の受信アンテナを有し、カプセル型内視鏡からの情報を周期的に取得する取得用アンテナと、複数の受信アンテナから得られた信号強度と前回複数の受信アンテナから得られた信号強度との差分値を算出する算出部(62)と、差分値と閾値とを比較して位置情報を推定するか否かを判断する判断部(63)と、判断部(63)が位置情報を推定すると判断した場合、カプセル型内視鏡の位置情報を推定する位置情報推定部(64)と、を備えた。
