An introducer sheath is disclosed having a high centering performance that is relatively easily capable of introducing an elongated body such as a catheter into an appropriate position, and is capable of appropriately maintaining hemostasis and insertibility of a valve body. The introducer sheath includes a tubular member provided with a hollow section through which an elongated body is freely insertable, a hub that includes an inner space which communicates with the hollow section of the tubular member and is provided on a proximal side of the tubular member, a valve body that is placed in the inner space of the hub, and an annular member that contacts with the valve body to fix the valve body to the inner space and includes a through-hole into which the elongated body can be inserted.