To provide powder safe and harmless to a human body and excellently used in drawing field lines or in preventing slippage.

A chicken egg shell E is washed with water, and dried in a hot-air dryer thereafter. The dried egg shell E is put into an agitating separation tank, where the egg shell is agitated with high-pressure water, and the egg membrane inside the egg shell E is separated and removed. After that, the egg shell E with the egg membrane separated and removed is dried in the hot-air dryer, and pulverized by a pulverizer into powder. The pulverized egg shell E is classified with a mesh screen, and the target egg shell powder P whose particle size is approximately 100 μm is obtained.