To obtain a detergent containing a bamboo charcoal, having good quality, and mild to the skin and the earth.

A raw bamboo is cut into a prescribed length, and split lengthwise (S1). The split bamboo is inserted into a smoking apparatus for four days to carry out a smoking treatment at 150-200°C (S2), and the treated bamboo is naturally dried for about three months (S3). The dried bamboo is carbonized in a charcoal furnace at 650-750°C (S4), and the obtained bamboo charcoal is pulverized and formed into fine powder (S5). The fine powder of the bamboo charcoal, and a detergent basis material are mixed, dissolved and saponified (S6), and the saponified product is solidified and cut into a prescribed largeness (S7) to provide the objective detergent.