PROBLEM TO BE SOLVED: To provide a soil-heating heater which can efficiently heat soil, can easily be treated and is inexpensive, and to provide a method for heating the soil with the heater. SOLUTION: The soil-heating heater 1 comprises a plate 2 comprising a porous material having good water resistance and heat resistance, a heater 3 disposed along the flat surface of the plate 2 and used for heating the plate 2, and a heat-insulating material 4 which covers the upper side of the plate 2 and prevents the release of heat from the upper side of the plate, wherein the lower side of the plate 2 is used as a grounding surface 2b to be grounded to the soil surface. The plate 2 is preferably formed from a raw material having a good water absorbing property and a good water-retaining property. The plate 2 is preferably formed by molding a pottery clay and then calcining the molded product. The plate 2 may also be formed by mixing a porous inorganic raw material such as a cement, zeolite, or diatomite with a hydration-reacting material such as lime or a cement, molding the mixture and then curing the molded product. The heating heater 1 is disposed on the ground surface on the periphery of a place where a cultivation plant 9 such as a fruit tree is planted, in a posture that the grounding surface 2b is disposed on the lower side. The upper side of the heater-disposed surface is covered with a heat release-preventing sheet 11 directly or so as to form a green house.
