Provided are a package of a mounting jig mounted balloon and a balloon mounting method capable of reducing the burden of an operation of mounting a balloon in an insertion part of an endoscope.A balloon includes a first sleeve part, a second sleeve part, and a balloon main body. A balloon mounting jig is formed to be folded flat in a hollow cylindrical shape, and has a main body having a first opening part and a second opening part, and a pair of guide pieces that is provided on the second opening part and face each other. A package of a mounting jig mounted balloon is configured so that the balloon mounting jig and the balloon are contained in the container, in which in the container, the balloon is disposed so that the second sleeve part is disposed inside the folded balloon main body and the pair of guide pieces is disposed inside the first sleeve part and the second sleeve part.
