To provide a harmless shell, employing a slug projectile (unit projectile) without destroying any nature and without breaking any gun even when the shell is used in a shot gun whose inner surface of a barrel is smooth, excellent in the accuracy of hitting and capable of hunting any large size animal such as deer or the like because of the power of the same.

The harmless shell for the shot gun is constituted of a unit projectile 2, a sabot 3, a wad 5, propellant 7 and a detonator 8 arranged sequentially, while the sabot 3 covering the unit projectile 2 from the outer side surface toward the bottom surface of the same has slits 9, provided on the sabot 3 so as to be divided equally into a plurality of sections in the circumferential direction and deepened gradually from the outside surface toward the bottom surface of the projectile.