Balloon folding method

A method of folding an inflatable balloon disposed on an outer peripheral surface of a shaft of a balloon catheter, the method comprising:

• arranging the balloon inside a plurality of first blade portions of a balloon folding device, the plurality of first blade portions being arranged so as to surround a linear reference position while maintaining a state where pressure is being applied to an inside of the balloon and wherein an axial center of the balloon is at a position deviated from the linear reference position, the linear reference position being a center of a center region of the plurality of first blade portions in which the balloon is arranged;
• rotating the plurality of first blade portions with respect to the balloon in the state where pressure is being applied to the inside of the balloon and moving the plurality of first blade portions toward the linear reference position in the state where the pressure is being applied to the inside of the balloon to move the axial center of the balloon to the linear reference position;
• and
• pleating a plurality of wing portions formed from the balloon and protruding radially outward on the balloon by further moving the plurality of first blade portions toward the linear reference position while gradually discharging a fluid from the inside of the balloon to partially press the balloon.