NOVELTY - A primary processor (1) heats and stirs the raw material (39) of organic wastes in a fermentation tank (2) in the presence of aerobic bacteria to dehydrate and ferment it to a preset level. The raw material from the primary processor is sent to a secondary processor which performs an aerobic treatment with an underground fermenter formed with an air permeable container.    USE - For processing organic substances such as organic refuse ejected from general homes, restaurants, various sludges and organic waste raw materials ejected from foodstuffs and fish processing factories, and converting them into a compost by the role of aerobic decomposition microbes for being used as manure for agriculture.    ADVANTAGE - A lot of raw materials can be processed in a small space efficiently, by dividing the processing system into a primary processor and a secondary processor. Miniaturization of the system is achieved. An efficient and inexpensive process is realized. The water content evaporation efficiency of the primary processor is improved by securing optimum conditions such as the amount of oxygen supply and internal pressure, by controlling the air intake into the fermentation container based on the detection value of the atmosphere inside the container and a specified decompression state is maintained. An effective usage of a secondary processor is achieved by using an underground fermenter without obstacles.    DETAILED DESCRIPTION - A primary processor (1) heats and stirs the raw material (39) of organic wastes in a fermentation tank (2) in the presence of aerobic bacteria to dehydrate and ferment it to a preset level. The raw material from the primary processor is sent to a secondary processor which performs an aerobic treatment with an underground fermenter formed with an air permeable container. The amount of air intake into the fermentation tank of the primary processor is controlled with a valve (35) opened and closed based on the signal of the pressure, temperature and humidity, detected by an atmosphere sensor (45) to maintain the internal pressure of the fermentation container to a preset pressure reduction value. The fermentation container of the secondary processor is formed, so that the raw material can be inserted and extracted by opening and closing a lid.    DESCRIPTION OF DRAWING(S) - The figure shows a flowchart of a primary processor for processing organic substances.    Primary processor (1)    Fermentation tank (2)    Valve (35)    Raw material of organic wastes (39)    Atmosphere sensor (45)