The present invention relates to an in vivo indwelling member which has loop-shaped parts, and a shape complicatedly curved in various directions. The in vivo indwelling member easily spreads inside the aneurysm during development due to strength thereof, is hardly entangled, and is easy to unravel, even if the in vivo indwelling member is concentrated in an overlapping manner. The in vivo indwelling member can maintain good operability and prevent the rupture and damage of the aneurysm. The in vivo indwelling member includes a plurality of loop-shaped parts (R01, R11, R21 to R23), each of which extends one turn or more to form a loop, the plurality of loop-shaped parts formed of loop-shaped parts with at least two different loop lengths from a tip end side of a primary coil toward a base end side of the primary coil.
