An object of the present invention is to provide a balloon catheter (10) capable of sufficiently transmitting torque, which is applied from a proximal side to the balloon catheter (10), to a front side of a balloon (20). The balloon catheter (10) includes a large-diameter coil part (32) formed of a stranded coil (31) arranged at a front side outer shaft (31), a small-diameter coil part (34) formed of a stranded coil (31) arranged at an extension part (52) of an inner shaft (50), and a transitional coil part (33) formed of a stranded coil (31) connecting the large-diameter coil part (32) and the small-diameter coil part (34). With this configuration, the torque can be transmitted from the front side outer shaft (31) to a front end of the extension part (52) of the inner shaft (50) through the stranded coil (31).
