To provide: a belt holder for easily holding a spare belt to be changed with an endless belt, allowing the spare belt to be easily removed and set to a rotation driving shaft and a roller when changing to the spare belt, and not limiting a position for holding the spare belt; and a method for holding the belt.

The belt holder 10 includes a mounting part 24 mounted to a frame 12, holding parts 26(1), 26(2) for holding the spare belt 21 in a state that the rotation driving shaft 18 penetrates the spare belt 21, and an arm part 28 extended from the mounting part 24 to the holding parts 26(1), 26(2).