PURPOSE: To accurately return the boomerang to the thrower by shifting the center of gravity of the center line of a blade backward and folding the rear edge of the blade at an angle.

CONSTITUTION: Three blades 1 are formed of paper in specific directions, and the center lines 2 of the respective blades are shifted backward from the positions of the centers 3 of gravity to obtain backward blades. Then the rear edges of the blades 1 are folded at an angle. Consequently, the track of the boomerang is held horizontal because of the effects of the backward blades and the boomerang returns to the thrower, so that the boomerang can easily be thrown indoors.