An indwelling needle includes a cylindrical main body to be fixed to a fitted body, a cylindrical hub for holding a needle, and a cylindrical protective cover which surround the needle and is provided slidably along the needle. In the usage state, the hub and the needle are advanced to the tip end side with respect to the main body and the protective cover is retreated to the rear end side with respect to the main body to project a cutting edge of the needle. In the housed state, the hub is retreated to the rear end side with respect to the main body, and the protective cover is advanced to the tip end side and the cutting edge of the needle is housed within the protective cover. Erroneous sticking into medical staff is prevented, and the burden on a patient is reduced.