Disclosed is an elasticity-controllable trampoline using a plate spring that can be manufactured in small size and in low height compared with existing trampolines using coil springs, thereby proving stability to a user. Also, it has a mechanical structure, thereby providing a semi-permanent life term. Under the principles of a lever using the third law of motion, particularly, the plate spring carries out action in smooth manner, in operation and also carries out reaction with the jumping operation of the user, such that the trampoline of the present invention will have strong elasticity. In addition, a plate spring support movable stand on the plate spring is moved in simple manner according to the principles of the lever, thereby allowing the elasticity of the plate spring to be controlled. With the adjustement of the upward and downward motion of an action point operation bolt, the height of the upward and downward motion can be adjusted. Specifically, the step plate is maintained at a horizontal state, upon upward and downward motion, by the adoption of a coupling movable member for maintaining the step plate horizontally, and a bearing sheet is formed on the step plate with a result that the step plate can carry out a twist motion.