To provide a hinge in which a hinge pin can be easily inserted/ removed into/from the hinge by fingers with an O-ring kept installed on the hinge pin without requiring a special tool, and in which the hinge pin can be held on the hinge when a door body is attached/detached to prevent loss of parts, and to improve door body attaching/detaching workability.

In this hinge 1, the O-ring 5 formed of rubber material is engaged in a groove 4a formed on the tip side of the hinge pin 4, and the hinge pin 4 is inserted into hinge pin inserting holes 2a, 3a, and 2b in the hinge 1 as the O-ring 5 is kept installed on the hinge pin 4. A tip of the hinge pin 4 and the O-ring 5 are protruded from a second box main body side hinge 2b, and the O-ring 5 is locked to an end of a the second box main body side hinge part 2d to prevent the hinge pin 4 from coming off. In attaching and detaching the door body, the hinge pin 4 is pulled off to a position where a tip of the hinge pin 4 is not protruded from a first box main body side hinge 2c, and as the hinge pin 4 is kept on the first box main body side hinge 2c, the door body is attached/detached.