A hinge includes a first part disposed in a first member and a second part disposed on a second member. The first part includes a first curved part with an arc shape protruding to outside in a radial direction of a rotational center, and a second curved part disposed outside the first curved part in the radial direction of the rotational center with spacing from the first curved part with an arc shape along the first curved part. The second part includes a connection disposed between the first curved part and the second curved part, wherein the connection moves smoothly along the first curved part and the second curved part about the rotational center. The second part couples, with the first part, the first member and the second member together to allow the first member and the second member to relatively rotate about the rotational center.