An elastic tube (40) is connected to the base end portion of a catheter body (1) having a balloon (2) at its top end portion. When the tube (40) is set at a vibrator device (RP), the end portion side of the tube, projecting outside, works as a margin volume portion (40A). A roller (53) of the vibrator device (RP) can have a shut-off state where the elastic tube (40) is pressed and completely closed, and a communication state where the tube cannot be pressed. When the roller (53) is rotated in a predetermined direction with the inside of a route from the balloon (2) up to the elastic tube (40) filled up with a liquid for heating, the liquid in the tube (40) is pressed toward the margin volume portion (40A) in the shut-off state, while in the communication state, the pressurized liquid in the margin volume portion (40A) flows back to the balloon side. Repeating the pressurizing and the- backflow vibrates the liquid in the balloon (2). When the balloon (2) is larger, the length (V) of the margin volume portion (40A) is made longer, so that adequate vibration in accordance with the size of the balloon can be applied.
