Enokitake (Flammulina velutipes) is one of the most popular cultivated mushrooms in Japan. A huge amount of waste culture is disposed thus its utilization as biomass fuel is needed. Due to high moisture content of waste mushroom culture, drying is necessary prior to use. As an approach for drying, compositing is proposed. Composters of various scale, from laboratory scale composter to semi-pilot scale composter (3 m^3 by volume) were operated. Temperature was measured during composting. A mathematical model is also proposed to predict the change in temperature.