Catheter and medical tube

Catheter (1; 2) comprising: a proximal shaft (15; 25) having a relatively high rigidity; a distal shaft (13; 23) connected to a front portion of said proximal shaft (15; 25) so as to be in fluid communication with the proximal shaft (15; 25) and having a lower stiffness of said proximal shaft (15; 25); a connecting sleeve (16; 26) disposed at the rear of said proximal shaft (15; 25) and configured to allow connection to a pressure applying apparatus to said sleeve (16; 26); a balloon (12; 22) disposed on the front face of said distal shaft (13; 23) so that it is in fluid communication with said distal shaft (13; 23) and configured to receive pressure applied from the sleeve connection (16; 26) and connected to the end face of end shaft (13; 23) at the back and projecting from the distal end of the distal shaft (13; 23); a cavity balloon for communicating said connection sleeve into said ball and socket of the guidewire to allow the guidewire is inserted through said cavity of the guidewire, including said cavity guidewire an opening distal (111; 211) located on the distal side relative to the front end of said balloon and a proximal aperture (141; 261; 262) located on the next back face with respect to the rear end of said ball; characterized in that at least a front portion, at the next back face relative to said ball (12; 22) of said distal shaft (13; 23) is formed as a part with grooves (131; 231; 331) having a groove (132; 232; 332), wherein said groove (132; 232; 332) it is formed with its depth changed so as to be large on the distal side of the part with grooves (131; 231 ; 331) and small on the proximal side of the part with grooves (131; 231; 331).