Catheter

A catheter that measures an internal temperature of a hollow organ inside a body, the catheter comprising:

• a catheter tube including a tip-flexible part and a base end part, the tip-flexible part being configured to perform a deflection operation, the base end part being provided at a base end of the tip-flexible part;
• and
• one or a plurality of temperature sensors provided in the tip-flexible part,
• the base end part including a first base end section and a second base end section,
• the first base end section being provided closer to the tip-flexible part than the second base end section, and having rigidity that is higher than rigidity of the tip-flexible part,
• the second base end section being provided at a base end of the first base end section, and having rigidity that is lower than the rigidity of the first base end section, wherein
• the tip-flexible part has a length in an axial direction of the tip-flexible part in a range from 40 mm to 100 mm,
• the first base end section has a length in an axial direction of the first base end section in a range from 200 mm to 400 mm,
• the second base end section has a length in an axial direction of the second base end section in a range from 200 mm to 900 mm, and
• a value of the rigidity of the first base end section and a value of the rigidity of the second base end section decrease linearly from the first base end section to the second base end section, in a region around a boundary between the first base end section and the second base end section.