To provide a fungus bed cultivation bag that prevents mushroom spawn film from tearing when the fungus bed is removed from the bag and can surely form the fungus bed in an appropriate shape. The fungus bed cultivation bag includes body parts opposing in the front and the back, a folding gusset part connecting to both sides of the body parts, a bottom seal part formed by heat-sealing the lower ends of the body parts and an inclined seal part formed by heat-sealing the lower end sides of the body parts and the folding gusset part in an oblique direction.