The aim of the present study is to develop the biomass furnace combustor, which can effectively use the compost as a fuel. Here, the compost that is made from pig's waste and has the calorific value of 2000kcal/kg is employed here. Emphasis is placed on the optimum conditions of fuel and air flow rates and moisture content of the compost and the corresponding combustion gas components and combustion gas temperature in the combustor. It is found from the study that (i) except 40% of the compost's moisture content, the self-combustion of compost as the fuel takes place, (ii) the combustion gas concentrations are affected by gas temperature, and (iii) the optimum value of the air-to-fuel ratio is obtained based on the gas temperature and the concentration of combustion gases. Copyright (c) 2016 John Wiley & Sons, Ltd.