A positional information acquisition device comprising: an image acquisition unit configured to acquire a radiographic image set including a plurality of radiographic images (G1,G2, GE1, GE2, GE11, GE12), which have been generated by alternately irradiating a subject with radiation emitted from a plurality of radiation sources (6A, 6B) provided at different positions (S1,S2) and alternately detecting the radiation transmitted through the subject using one detection unit, at a predetermined time interval; a feature point detection unit configured to detect at least one common feature point in the subject from each of the plurality of radiographic images (G1,G2, GE1, GE2, GE11, GE12) included in the radiographic image set; a positional information derivation unit configured to derive three-dimensional positional information of the at least one feature point in the subject using a positional relationship between a position of the at least one feature point detected from each of the plurality of radiographic images (G1,G2, GE1, GE2, GE11, GE12) on a detection surface of the detection unit and positions of the plurality of radiation sources (6A, 6B), the feature point being a point on a surgical instrument inserted into the subject; and a display control unit configured to display the positional information on a display unit, whereby a positional information screen is displayed having (i) a radioscopic image display region and a (ii) positional information display region for the positional information P0, the radioscopic image display region and positional information display region including images corresponding to imaging in different directions; wherein radioscopic images are displayed in the radioscopic image display region as a moving image, the radioscopic images including sequentially displayed first radiographic images G1 and sequentially displayed second radiographic images G2, wherein the positional information P0 is displayed in the positional information display region using the three-dimensional information of a target structure derived by a three-dimensional information derivation unit, the positional information P0 schematically indicating the shape and position of the target structure and the position of the surgical instrument. an image acquisition unit configured to acquire a radiographic image set including a plurality of radiographic images (G1,G2, GE1, GE2, GE11, GE12), which have been generated by alternately irradiating a subject with radiation emitted from a plurality of radiation sources (6A, 6B) provided at different positions (S1,S2) and alternately detecting the radiation transmitted through the subject using one detection unit, at a predetermined time interval; a feature point detection unit configured to detect at least one common feature point in the subject from each of the plurality of radiographic images (G1,G2, GE1, GE2, GE11, GE12) included in the radiographic image set; a positional information derivation unit configured to derive three-dimensional positional information of the at least one feature point in the subject using a positional relationship between a position of the at least one feature point detected from each of the plurality of radiographic images (G1,G2, GE1, GE2, GE11, GE12) on a detection surface of the detection unit and positions of the plurality of radiation sources (6A, 6B), the feature point being a point on a surgical instrument inserted into the subject; and a display control unit configured to display the positional information on a display unit, whereby a positional information screen is displayed having (i) a radioscopic image display region and a (ii) positional information display region for the positional information P0, the radioscopic image display region and positional information display region including images corresponding to imaging in different directions; wherein radioscopic images are displayed in the radioscopic image display region as a moving image, the radioscopic images including sequentially displayed first radiographic images G1 and sequentially displayed second radiographic images G2, wherein the positional information P0 is displayed in the positional information display region using the three-dimensional information of a target structure derived by a three-dimensional information derivation unit, the positional information P0 schematically indicating the shape and position of the target structure and the position of the surgical instrument.