Patent ID: 7744203

Claim:
A needle that pierces an elastic body, which is stopping a flow passage, so as to interconnect regions of the passage, which are separated by the elastic body, the needle comprising: a hollow pipe that pierces the elastic body, one longitudinal end of the hollow pipe being closed; a through hole formed through a wall of the hollow pipe; and a recessed curved area formed on the wall of the hollow pipe around the through hole, the wall being bent in the recessed curved area such that outer and inner surfaces of the wall are the more inside of the hollow pipe along a central axis of the through hole, at the nearer position to the central axis, the recessed curved area being formed such that the distance between an end of a contour of the recessed curved area at which a straight line extending longitudinally of the hollow pipe through the central axis of the through hole intersects with the contour of the recessed curved area, and an end of the through hole that is the nearest to the end of the contour of the recessed curved area longitudinally of the hollow pipe, is larger than the distance between an end of the contour of the recessed curved area at which a straight line extending laterally of the hollow pipe through the central axis of the through hole intersects with the contour of the recessed curved area, and an end of the through hole that is the nearest to the end of the contour of the recessed curved area laterally of the hollow pipe, when viewed along the central axis of the through hole.