A placement device (11) is provided for causing a catheter (76) to place an inside of a body. The placement device (11) includes: an insertion unit (12) that is flexible and that is insertable into and removable from the catheter (76), the insertion unit being capable of observing an object located more distally than a distal end of the insertion unit； a transmission unit (36) that has a first connecting portion (38) to be detachably connected to a proximal end portion of the insertion unit (12), and that transmits an image obtained by observation of the insertion unit (12) or a signal obtained by converting the image, and； a supply member (61) into which the insertion unit (12) is to be inserted so as to be drawable therefrom, and to which a proximal end portion of the catheter (76) is to be detachably attached. The supply member (61) includes a supply unit main body (62) into which the insertion unit (12) is to be inserted, and a projection (63) which is formed of an elastic material over an entire periphery of the supply unit main body (62) on an inner peripheral surface of the supply unit main body (62), and which contacts with the insertion unit hermetically and holds the insertion unit such that the insertion unit (12) is capable of sliding. A through-hole (62a) is formed on the inner peripheral surface of the supply unit main body (62) at a position closer to a distal end side of the supply portion main body (62) than the projection (63), and the through-hole (62a) communicates with an inside of the supply unit main body (62) at the distal end side of the supply unit main body (62).
