Use of a graphite material for a graphite heater utilizing Joule heat generation, wherein the graphite material has a product (Lc × La × P1) of 1900 nm 2 or more and 5000 nm 2 or less, a specific resistance at 25°C (ρ 25) of 10.0 μΩ·m or more and 12.0 μΩ·m or less, a specific resistance at 1600°C (ρ 1600) of 9.5 μΩ·m or more and 11.0 μΩ·m or less, a ratio (ρ 1600 /ρ 25) of specific resistance at 1600°C to that at 25°C of 0.85 or more and 1.00 or less, a temperature at which the minimum specific resistance (ρ min) appears of 500°C or higher and 800°C or lower, a ratio (ρ min /ρ 25) of the minimum specific resistance to the specific resistance at 25°C of 0.70 or more and 0.80 or less, a bulk density of 1.69 g/cm 3 or more and 1.75 g/cm 3 or less, wherein Lc is a size of a crystallite in a c-axis direction, indicating a thickness of stacked carbon net plane layers, La is a size of a crystallite in an a-axis direction, indicating a spread of a carbon net plane, and P1 indicates a graphitization degree; and wherein the graphite material is obtained by a manufacturing method having the following steps: a step of pulverizing an aggregate which is used as a raw material to a predetermined size; a step of mixing the pulverized aggregate and a binder at a ratio of 50 to 30 parts by weight of the binder for 50 to 70 parts by weight of the aggregate, and kneading the mixture while heating; a step of pulverizing the intermediate material which is the kneaded product to a prescribed particle size, and filling the material into a rubber mold for shaping; a step of heating and burning the resulting formed product in a non-oxidizing atmosphere; and a step of heating the burnt product in a non-oxidizing atmosphere so as to raise the temperature of the burnt product from 2800°C up to 3000°C for graphitization; wherein the aggregate, which is used as a raw material, is selected from: 1 a mixed raw material of 40 to 60 parts by weight of a needle pitch coke in which the crystal textures are aligned in one direction, and 40 to 60 parts by weight of random amorphous pitch coke in which the crystal directions are random; and 2 a mixed raw material of 40 to 60 parts by weight of a pitch coke and 40 to 60 parts by weight of a graphite. Lc is a size of a crystallite in a c-axis direction, indicating a thickness of stacked carbon net plane layers, La is a size of a crystallite in an a-axis direction, indicating a spread of a carbon net plane, and P1 indicates a graphitization degree; and wherein the graphite material is obtained by a manufacturing method having the following steps: a step of pulverizing an aggregate which is used as a raw material to a predetermined size; a step of mixing the pulverized aggregate and a binder at a ratio of 50 to 30 parts by weight of the binder for 50 to 70 parts by weight of the aggregate, and kneading the mixture while heating; a step of pulverizing the intermediate material which is the kneaded product to a prescribed particle size, and filling the material into a rubber mold for shaping; a step of heating and burning the resulting formed product in a non-oxidizing atmosphere; and a step of heating the burnt product in a non-oxidizing atmosphere so as to raise the temperature of the burnt product from 2800°C up to 3000°C for graphitization; wherein the aggregate, which is used as a raw material, is selected from: 1 a mixed raw material of 40 to 60 parts by weight of a needle pitch coke in which the crystal textures are aligned in one direction, and 40 to 60 parts by weight of random amorphous pitch coke in which the crystal directions are random; and 2 a mixed raw material of 40 to 60 parts by weight of a pitch coke and 40 to 60 parts by weight of a graphite. a step of pulverizing an aggregate which is used as a raw material to a predetermined size; a step of mixing the pulverized aggregate and a binder at a ratio of 50 to 30 parts by weight of the binder for 50 to 70 parts by weight of the aggregate, and kneading the mixture while heating; a step of pulverizing the intermediate material which is the kneaded product to a prescribed particle size, and filling the material into a rubber mold for shaping; a step of heating and burning the resulting formed product in a non-oxidizing atmosphere; and a step of heating the burnt product in a non-oxidizing atmosphere so as to raise the temperature of the burnt product from 2800°C up to 3000°C for graphitization; wherein the aggregate, which is used as a raw material, is selected from: 1 a mixed raw material of 40 to 60 parts by weight of a needle pitch coke in which the crystal textures are aligned in one direction, and 40 to 60 parts by weight of random amorphous pitch coke in which the crystal directions are random; and 2 a mixed raw material of 40 to 60 parts by weight of a pitch coke and 40 to 60 parts by weight of a graphite. 1 a mixed raw material of 40 to 60 parts by weight of a needle pitch coke in which the crystal textures are aligned in one direction, and 40 to 60 parts by weight of random amorphous pitch coke in which the crystal directions are random; and 2 a mixed raw material of 40 to 60 parts by weight of a pitch coke and 40 to 60 parts by weight of a graphite.