The present invention relates to a balloon catheter. The invention comprises: a first shaft； an expandable balloon which is attached to the front end of the first shaft； an expandable lumen which is formed inside the first shaft and to which a liquid required for expanding the balloon is provided； a second shaft which extends from the front end of the first shaft to which the balloon is attached and has a wire hole through which a guide wire passes； and a guide wire lumen, which is formed inside the second shaft and through which the guide wire passes. According to the invention, the first and second shafts are coaxially connected and the expandable lumen and the guide wire lumen are respectively formed in each shaft in order to reduce the overall diameter of the shaft, thereby facilitating surgery and improving pushability.
