To provide a gem holding gadget which can securely and easily hold a facet-cut gem or a synthetic stone by one radial directional side.

This holding gadget is integrally formed with a hook section which is touchingly applied to a crown or a crown and table of the facet-cut gem, a side applying section which is touchingly applied to a pavilion, and a supporting seat which supports the periphery of a culet. After the gem is insertedly held between the hook section and the supporting seat, a stopper cylinder is driven up into an open hole portion which is bored adjoiningly to the bottom end of the supporting seat, and the gem is pushed up and fixed.