A probe shape detection apparatus comprising: a magnetic field sensing section adapted to sense a magnetic field generated when an alternating current signal is applied to a plurality of source coils (14a to 14p) which are provided in a probe having flexibility; a coordinate computation section adapted to perform a computational operation to calculate three-dimensional coordinates which represent positions of the plurality of source coils (14a to 14p) based on the magnetic field sensed by the magnetic field sensing section; a movement speed calculation section adapted to calculate a movement speed of the plurality of source coils (14a to 14p) based on the three-dimensional coordinates calculated by the coordinate computation section or on a signal sensed by an acceleration sensor, provided in the probe; characterised in that the probe shape detection apparatus further comprises; a moving average coordinate calculation section adapted to calculate moving average coordinates within a predetermined period based on a plurality of sets of three-dimensional coordinates of the plurality of source coils (14a to 14p) detected by the coordinate computation section within the predetermined period; a comparison section adapted to compare the movement speed calculated by the movement speed calculation section with a predetermined threshold; a coil coordinate setting section adapted to set the moving average coordinates as model coordinates of the plurality of source coils (14a to 14p) when a comparison result produced by the comparison section indicates that the movement speed is lower than the predetermined threshold and set the three-dimensional coordinates calculated by the coordinate computation section as the model coordinates of the plurality of source coils (14a to 14p) when the comparison result indicates that the movement speed is equal to or higher than the predetermined threshold; and a control section adapted to generate display data to be displayed as a scope model corresponding to a shape of the probe by using data of the model coordinates set by the coil coordinate setting section. a magnetic field sensing section adapted to sense a magnetic field generated when an alternating current signal is applied to a plurality of source coils (14a to 14p) which are provided in a probe having flexibility; a coordinate computation section adapted to perform a computational operation to calculate three-dimensional coordinates which represent positions of the plurality of source coils (14a to 14p) based on the magnetic field sensed by the magnetic field sensing section; a movement speed calculation section adapted to calculate a movement speed of the plurality of source coils (14a to 14p) based on the three-dimensional coordinates calculated by the coordinate computation section or on a signal sensed by an acceleration sensor, provided in the probe; characterised in that the probe shape detection apparatus further comprises; a moving average coordinate calculation section adapted to calculate moving average coordinates within a predetermined period based on a plurality of sets of three-dimensional coordinates of the plurality of source coils (14a to 14p) detected by the coordinate computation section within the predetermined period; a comparison section adapted to compare the movement speed calculated by the movement speed calculation section with a predetermined threshold; a coil coordinate setting section adapted to set the moving average coordinates as model coordinates of the plurality of source coils (14a to 14p) when a comparison result produced by the comparison section indicates that the movement speed is lower than the predetermined threshold and set the three-dimensional coordinates calculated by the coordinate computation section as the model coordinates of the plurality of source coils (14a to 14p) when the comparison result indicates that the movement speed is equal to or higher than the predetermined threshold; and a control section adapted to generate display data to be displayed as a scope model corresponding to a shape of the probe by using data of the model coordinates set by the coil coordinate setting section.