To provide a method for coloring a food material by which the food material hardly being colored, such as a boiled egg is easily colored in a desired color or pattern by using a coloring matter derived from a natural product.

A black ancient rice in an amount of three tablespoonfuls and three boiled eggs after peeling the shells are inserted into 700 cc water, and the water including the rice and the eggs is heated. When the temperature of the water reaches about 95°C, the not-boiling temperature is kept. After boiling the eggs at the temperature for about 20 min, vinegar is added thereto. The eggs are allowed to stand in the soaked state for about 8 hr. When the resultant eggs are taken out from the water, the surfaces of the eggs have been colored in deep green.