To provide a circulation type biomass boiler system, which dries refuse such as a mushroom waste medium, garbage or the like, heats a boiler with the dried refuse as fuel and generates steam, on the other hand, dries the refuse by utilizing the waste heat of the boiler thereby producing fuel in house.

This biomass boiler system is characterized by being constituted of: a boiler device which generates steam by utilizing a dried object of the refuse such as the mushroom waste medium, the garbage or the like as fuel; a dryer which dries the refuse by utilizing the waste heat of the boiler device; and a supply device which supplies the dried refuse to the boiler device.