In an indwelling device for embolization comprising a coil portion (11) having a proximal side and a distal side and having a lumen extending in a longitudinal direction, and a stretch-resistant member (20) disposed in the lumen, a spring constant of the coil portion (11) is 1.0 N/mm or less, the stretch-resistant member (20) has a waveform, and a wave height, which is a distance between peaks on an inner side of the waveform of the stretch-resistant member (20), is 35 µm or larger and smaller than an inner diameter of the coil portion (11), in order to provide the indwelling device for embolization that suppresses changes in dimension of the coil portion (11) during sterilization.
