PROBLEM TO BE SOLVED: To provide a capsule type endoscope system capable of detecting the position of a capsule type endoscope device with higher accuracy than in the conventional practice while suppressing a calculation amount, and to provide a position determination method and a program.SOLUTION: The capsule type endoscope system includes a distance calculation part 562 for calculating a distance between each reception antenna and the capsule type endoscope device on the basis of the direction of the capsule type endoscope device to a reception antenna unit detected by a direction detection part 561 and the reception intensity of each reception antenna calculated by the reception intensity calculation part, a theoretical value calculation part 564 for calculating a theoretical value of the reception intensity of a radio signal received by each reception antenna in the case of assuming that the capsule type endoscope device exists at each point on the basis of each of a plurality of points within an area acquired by an area calculation part 563, and a position determination part 565 for determining a point where a difference between the theoretical value calculated by the theoretical value calculation part 564 and the reception intensity calculated by the reception intensity calculation part becomes smallest as the position of the capsule type endoscope device among a plurality of points.
