A driving signal is supplied from a transmission block to a magnetic-field generating element arranged on either one of an inside of an endoscope insertion portion and an outside of an endoscope. A magnetic field generated by the magnetic-field generating element is detected by a magnetic-field detecting element arranged on the other and the signal is received by a receiving block. For the signal from the receiving block, control processing including processing for calculating the shape of the endoscope insertion portion is carried out from position information of the magnetic-field generating element or the magnetic-field detecting element arranged inside the endoscope insertion portion. The receiving block provided with an amplification circuit for at least amplifying the signal detected by the magnetic-field detecting element is formed separately from the transmission block and the control block.
