A stent to be implanted in a living body is formed substantially as a tube having a form in which plural wavy annular members are arranged adjacent to each other in the axial direction of the stent, with the axially adjacent wavy annular members connected to each other. The stent possesses an outer diameter whose dimension is so set that the stent is insertable into a lumen inside a living body, and is expandable when a force spreading radially from the inside of the tube is applied. The wavy annular member has parallel straight-line portions extending parallel to the axis of the stent before and after the stent expands. The stent has connection portions each connecting ends of the parallel straight-line portions of the adjacent wavy annular members to each other.
