To provide an oils fats removing device of a simple structure capable of removing oils and fats in waste water for a long period only by throwing the device onto the surface of waste water in a conventional waste water tank.

The oils and fats removing tool is obtained by mounting a circular floating body in a circular outer body formed of a coarse net, baking and hardening fine powders of stone, etc., so as to include countless minute appertures between the outer body and the floatin body and filling the minute appertures with small lumps incorporating and carrying the spores of microorganism, etc., having an oils and fats decomposition power.