Abstract: A tubular indwelling device is accurately placed at a placement target site in a biological lumen. A catheter (1) is a catheter for delivering a colonic stent (2) to be placed in a biological lumen, including: a sheath (11); an inner tube (12) configured to be movable in the sheath in an axial direction; and converting means (20) capable of maintaining at least a portion of the colonic stent in the axial direction in a contracted state in a state in which the colonic stent is released from the sheath and converting the portion from the contracted state to an expanded state. The inner tube is provided with a guide rib (30) that holds the converting means, and the guide rib is formed to be able to position the colonic stent in the contracted state in an axial direction of the inner tube.