To solve a problem in which chlorine is produced in a process of the production even if a pure soap, moreover a synthetic detergent is accompanied by the extinction of a microorganism for the sake of the decomposition in natural world, and they take on the danger of destroying continuous biomass environment.

The detergent using α starch which is food and harmless even if an organism takes in can be obtained in a suitable manner for the environment from a paddy field, upland farming or the like. Moreover, the liquid after washing animal oil or vegetable oil by the detergent can be returned to soil, whereby the enrichment is promoted. For example, meat or fish is cooked with a wok, if rice cooked is simultaneously put into the wok together, is mixed and is eaten, the wok is washed by water by a bamboo or wooden washing instrument or the like, whereby the oil can be washed out. Moreover, if cooked rice is dressed in the juice which has remained in the pan after carrying out meat or fish dish by a wok or the like, seasoned with a seasoning of preference, mixed and eaten, the oil can be flushed similarly.