The shaft (12) of a catheter (10A) has an inner layer (20) and an outer layer (22) provided on the outside of the inner layer (20). At least a portion of the leading end (20a) of the inner layer (20) is present inside a soft tip (14). In a transverse cross-section comprising the leading end (20a) of the inner layer (20), inner layer-comprising regions (30) in which the inner layer (20) is present and inner layer-less regions (32) in which the inner layer (20) is not present are formed along the circumferential direction. The catheter use method comprises a presentation step for presenting the catheter (10A) and a running step in which the catheter (10A) is inserted and run inside a blood vessel or a body cavity.
