To provide a method for producing a culture medium in which high-quality culture medium can favorably be produced and to provide an Agaricus blazei mushroom product.

In the method for producing the culture medium, a salt (salt water 20) is added to a culture medium material 10 and the culture medium material 10 is fermented or the culture medium material 10 in which a bamboo material 12 is mixed is used and the culture medium material 10 is fermented or the culture medium material 10 is packed in a wooden container 50 and the culture medium material 10 is fermented or the culture medium material 10 is housed in a hermetically sealed chamber and the culture medium material 10 is fermented. The Agricus blazei mushroom product is obtained by pulverizing Agricus blazei mushroom or extracting an extract of the Agricus blazei mushroom and contains a salt. The Agricus blazei mushroom product is obtained by pulverizing Agricus blazei mushroom or extracting the extract of the Agricus blazei mushroom and uses the mycelium and the fruit body as raw materials for Agricus blazei mushroom.