Abstract: A system for manufacturing a solid medium for cultivating mushrooms includes a mixer for mixing and agitating medium materials, and a heater coupled to the mixer for sterilizing the medium materials from the mixer with the heat of steam. The sterilized medium materials are then delivered into a cooler connected to the heater, and cooled and moistened by water scattered by a sprinkler. The cooler is coupled to a mycelia supply source for supplying mycelia of the mushroom with which the cooled medium materials are spawned. The solid medium thus produced is then packaged by a packaging mechanism in a germ-free environment.