Indwelling needle

An indwelling needle comprising a needle having a sharp edge formed at the tip thereof, a tubular hub for holding the needle, and a tubular protective cover surrounding the needle and slidable along the needle,

• the indwelling needle being switchable between a use state in which the protective cover is relatively moved toward the proximal end of the needle so that the sharp edge of the needle projects from the protective cover and a housed state in which the protective cover is relatively moved toward the distal end of the needle so that the sharp edge of the needle is housed in the protective cover, characterized in that;
• the hub has a tubular body slidably provided therein, the body having the protective cover slidably provided therein so that the needle slidably passes through the body and the protective cover, while a spring is elastically fitted between the body and the protective cover so as to urge the body and the protective cover toward the proximal end and the distal end, respectively,
• further comprising a first retention mechanism between the body and the hub for retaining the hub and the needle in the use state in which the hub and the needle is advanced toward the distal end relative to the body, and a second retention mechanism between the body and the protective cover for retaining the protective cover in the use state in which the protective cover is retracted toward the proximal end relative to the body against elastic force of the spring,
• and the second retention mechanism is released by releasing the first retention mechanism so that the hub is retracted relative to the body into the housed state, thereby the protective cover is advanced relative to the body with the elastic force of the spring to achieve the housed state.