A balloon catheter of the present invention has an outer tube having a first lumen inside it. At the distal end of the outer tube is connected the proximal end of the balloon portion so that a balloon space is formed inside it, the distal end of the balloon portion is joined to a cylindrical front tip portion, and pressurized fluid is introduced into and released from the balloon space through the first lumen of the outer tube so as to make the balloon portion expand or contract. Inside the first lumen of the outer tube is arranged an inner tube having a second lumen freely slidable in the axial direction. The distal end of the inner tube projects out from the distal end of the outer tube and is detachably attached to the front tip portion. The balloon catheter of the present invention may have a guidewire detachably attached to the front tip portion rather than providing the inner tube.