A fungal bed cultivation method of a hon-shimeji mushroom, in which the sprouting step and/or fruit body growing step is carried out under an environmental condition of high CO2 concentration, is provided. Examples of the environmental condition of high CO2 concentration include a CO2 concentration of 2,500 ppm or more in the sprouting step and a CO2 concentration of 5,000 ppm or more in the fruit body growing step. Since the formation ratio of a budlet in the fungal bed cultivation of a hon-shimeji mushroom is improved by embodiments of the present invention, stable production of a hon-shimeji mushroom by its large scale commercial cultivation becomes possible.
