Provided are: an imaging device which can be miniaturized and which has excellent connection reliability； an endoscope system； and a method for manufacturing the imaging device. This imaging device 100 includes: an imaging element 10 which has a light reception unit 12a and multiple sensor electrodes 13； a relay board 20 which has two boards 21 and 23, an electronic component 28 mounted on the board 23, a main body portion 22 in which the electronic component 28 is sealed with a sealing resin, board electrodes 26 which are formed on the front, cable electrodes 24 which are formed on the back, and multiple pins 27 erected on the board 21, said relay board having the board electrodes 26 connected with the sensor electrodes 13； and an assembled cable 30 which has multiple cables 31 and a cable securing member 32 which secures the cables 31, said assembled cable having core wires 34 which are exposed on a connection surface of the cable securing member 32 being connected with the cable electrodes 24. The imaging device 100 is characterized in that the coefficient of thermal expansion of the imaging element 10, the coefficient of thermal expansion of the relay board 20, and the coefficient of thermal expansion of the assembled cable 30 change incrementally in descending or ascending order.La présente invention concerne : un dispositif d'imagerie qui peut être miniaturisé et qui a une excellente fiabilité de connexion ； un système d'endoscope ； et un procédé de fabrication du dispositif d'imagerie. Ce dispositif d'imagerie 100 comprend : un élément d'imagerie 10 qui comporte uneunité de réception de lumière 12a et des électrodes de capteur multiples 13 ； une carte de relais 20 qui comporte deux cartes 21 et 23, un composant électronique 28 monté sur la carte 23, une partie de corps principal 22 dans laquelle le composant électronique 28 est scellé avec une résine de scellement, des électrodes de carte 26 qui sont formées à l'avant, des électrodes de câble 24 qui sont form
