A stent placement device capable of forward/backward operation for adjusting a placement position of a stent in a living tissue and forward/backward operation in a treatment instrument insertion channel of an ultrasonic endoscope is realized by providing a guide tube 15 holding a stent 22 to be placed in an opening formed in a tissue of a body cavity so as to move forward/backward in the axial direction, a fixing portion provided at a tip end of the guide tube 15 and including a claw portion 15a and a reduced-diameter portion 15b which is changeable between a locked position and a nonlocked position of the stent 22 when the stent 22 is held by the guide tube 15, and an operation portion 12 for operating a pusher tube 20 or the like operating movement of the stent 22 of the fixing portion between the locked position and the nonlocked position.
