A distinguishing method of a graphene precursor with respect to graphite raw material in which a hexagonal crystal system graphite layer and a rhombohedral crystal system graphite layer are mixed, the method comprising the steps of: specifying a zero-point of a diffraction angle from at least one peak position of a diffracted beam by lattice planes of c-axis direction for powder X-ray diffraction data of the graphite raw material; calculating peak positions specific to the hexagonal crystal system graphite layer and the rhombohedral crystal system graphite layer from the specified zero-point, by assuming that an interplanar spacing between graphene sheets that form the graphite raw material is the same in any graphite layer mixed in the graphite raw material and that a crystal structure inside the graphene sheets is the same in any graphite layer mixed in the graphite raw material, wherein the a-axis and b-axis lengths of the hexagonal crystal system graphite layer 2H in the graphite raw material are equal to the a-axis and b-axis lengths of the rhombohedral crystal system graphite layer 3RH therein, respectively; and the c-axis length of the hexagonal crystal system graphite layer 2H is 2/3 times the c-axis length of the rhombohedral crystal system graphite layer 3RH; calculating integrated intensities at the peak positions refined by profile fitting, with the calculated peak positions as initial values, based on the profile fitting; and determining whether or not a rate of an integrated intensity value of a 101 diffracted beam of the hexagonal crystal system graphite layer to an integrated intensity value of a 101 diffracted beam of the rhombohedral crystal system graphite layer at the calculated peak positions is the same as or higher than a predetermined value, based on the calculated integrated intensities; and determinably outputting that the graphite raw material is the graphene precursor when it is determined that the rate with regard to the integrated intensity values is the same as or higher than the predetermined value, and that the graphite raw material is not the graphene precursor when it is determined that the rate with regard to the integrated intensity values is lower than the predetermined value. specifying a zero-point of a diffraction angle from at least one peak position of a diffracted beam by lattice planes of c-axis direction for powder X-ray diffraction data of the graphite raw material; calculating peak positions specific to the hexagonal crystal system graphite layer and the rhombohedral crystal system graphite layer from the specified zero-point, by assuming that an interplanar spacing between graphene sheets that form the graphite raw material is the same in any graphite layer mixed in the graphite raw material and that a crystal structure inside the graphene sheets is the same in any graphite layer mixed in the graphite raw material, wherein the a-axis and b-axis lengths of the hexagonal crystal system graphite layer 2H in the graphite raw material are equal to the a-axis and b-axis lengths of the rhombohedral crystal system graphite layer 3RH therein, respectively; and the c-axis length of the hexagonal crystal system graphite layer 2H is 2/3 times the c-axis length of the rhombohedral crystal system graphite layer 3RH; calculating integrated intensities at the peak positions refined by profile fitting, with the calculated peak positions as initial values, based on the profile fitting; and determining whether or not a rate of an integrated intensity value of a 101 diffracted beam of the hexagonal crystal system graphite layer to an integrated intensity value of a 101 diffracted beam of the rhombohedral crystal system graphite layer at the calculated peak positions is the same as or higher than a predetermined value, based on the calculated integrated intensities; and determinably outputting that the graphite raw material is the graphene precursor when it is determined that the rate with regard to the integrated intensity values is the same as or higher than the predetermined value, and that the graphite raw material is not the graphene precursor when it is determined that the rate with regard to the integrated intensity values is lower than the predetermined value.