To provide a balloon-pressurizing device which gives less damage on a lesional site and which causes hardly a restenosis after a therapy or a delayed thrombosis in the therapy using a balloon catheter.

The balloon-pressurizing device 1 comprises a connector 2 capable of connecting a base end opening of a balloon lumen connecting with a balloon 130 of the balloon catheter 100, a reservoir 3 for storing an operating fluid, a means 4 for pressurizing to a predetermined pressure in the reservoir 3, a circulating passage 5 of the fluid formed via the reservoir 3, and a pressure change means 6 provided on the way of the passage 5 to generate a pulsation flow. The balloon 130 is pressurized by the means 4 and the means 6 so as to periodically change the pressure. Thus, the balloon 130 is vibrated in an enlarged state, and enlarges the lesional site while imparting a vibration to the site.