PROBLEM TO BE SOLVED: To provide a heat sterilization method for soil capable of effectively killing pathogenic microorganisms in soil. SOLUTION: Plural pipes 3 are buried in the soil in a greenhouse 2 at a depth of 40-80 cm from the ground surface, the soil is warmed by passing hot water or hot liquid into the pipes 3. When this ground warming apparatus is used, the temperature in the soil is elevated due to both solar heat and underground warming to perform heat sterilization of the soil 4. Or, hot air is sent into soil by supplying hot air in stead of hot water or hot liquid into perforated pipes buried in the ground, and thus the temperature of the soil is elevated. Thus, the temperature of the soil at 60 cm depth from the ground surface is effectively elevated to 50-60 deg.C, and the soil within 60 cm in depth can be completely sterilized.
