A fluid supply body for supplying a fluid to a balloon formed of a material having elasticity and inflating the balloon, the fluid supply body includes a cylinder, a plunger, an adjusting portion that is attached to the plunger and adjusts the movement, amount of the plunger so that the balloon is inflated with to a predetermined inflation diameter, and a fixing portion that is provided at the cylinder and fixes the plunger at a position within the cylinder corresponding to the movement amount adjusted by the adjusting portion, wherein the adjusting portion has a plurality of engaging portions that, specify movement amounts corresponding to a plurality of different inflation diameters of the balloon, and the fixing portion has an engaged portion, and a converting portion.