To provide a food of Agaricus mushroom mycelium mass capable of uniformly growing a large amount of Agaricus mushroom mycelia in a culture medium in a short period, readily carrying out process for producing mycelium mass food and transportation of the product and efficiently taking active ingredients of Agaricus mushroom mycelia.

Crude wheat 1 which is grains before purification having an epidermal layer 2a favorably keeping a grain shape in swelling is swollen and saturated with water and sterilized by steam cooking and the steam-cooked and swollen crude wheat is packed as a culture medium 4 into a culturing bag 3 while maintaining spaces R among grains and Agaricus mushroom spawn 5 is inoculated into the culture medium 4. After mycelia 6 is grown in a considerable volume, the grown mycelia are heated to provide the health food material.