A navigation device used for an endoscope having an insertion part to be inserted into a subject, an imaging element provided on a distal end side of the insertion part, and a plurality of magnetic field detection units that are provided within the insertion part and detect magnetic fields, the navigation device comprising: a magnetic field generation control unit configured to cause the magnetic fields to be generated at different timings from a plurality of magnetic field generation units that generate the magnetic fields at mutually different positions; an image signal acquisition unit configured to acquire, from the endoscope, an added image signal obtained by adding specification information for specifying the magnetic field generation units generating the magnetic fields and magnetic field detection results of the respective magnetic field detection units to an image signal output from the imaging element; and a position detection unit configured to detect positions of the respective magnetic field detection units on the basis of the specification information and the magnetic field detection results that are added to the added image signal acquired by the image signal acquisition unit, wherein the image signal is a plurality of frame image signals that constitute a dynamic image, and the added image signal is added frame image signals obtained by adding the specification information and the magnetic field detection results to the frame image signals, wherein the specification information is frame start signals showing start of the added frame image signals, wherein the magnetic field generation control unit configured to perform switching of the magnetic field generation units generating the magnetic fields on the basis of the frame start signals added to the added frame image signals acquired by the image signal acquisition unit, and wherein the position detection unit configured to perform determination processing of determining a correspondence relationship between the magnetic field detection results added to the added frame image signals and the magnetic field generation units, on the basis of the frame start signals added to the added frame image signals, and position detection processing of detecting the positions of the respective magnetic field detection units from the magnetic field detection results, on the basis of the correspondence relationship determined by the determination processing. a magnetic field generation control unit configured to cause the magnetic fields to be generated at different timings from a plurality of magnetic field generation units that generate the magnetic fields at mutually different positions; an image signal acquisition unit configured to acquire, from the endoscope, an added image signal obtained by adding specification information for specifying the magnetic field generation units generating the magnetic fields and magnetic field detection results of the respective magnetic field detection units to an image signal output from the imaging element; and a position detection unit configured to detect positions of the respective magnetic field detection units on the basis of the specification information and the magnetic field detection results that are added to the added image signal acquired by the image signal acquisition unit, wherein the image signal is a plurality of frame image signals that constitute a dynamic image, and the added image signal is added frame image signals obtained by adding the specification information and the magnetic field detection results to the frame image signals, wherein the specification information is frame start signals showing start of the added frame image signals, wherein the magnetic field generation control unit configured to perform switching of the magnetic field generation units generating the magnetic fields on the basis of the frame start signals added to the added frame image signals acquired by the image signal acquisition unit, and wherein the position detection unit configured to perform determination processing of determining a correspondence relationship between the magnetic field detection results added to the added frame image signals and the magnetic field generation units, on the basis of the frame start signals added to the added frame image signals, and position detection processing of detecting the positions of the respective magnetic field detection units from the magnetic field detection results, on the basis of the correspondence relationship determined by the determination processing.