A method of calculating an electrode density of an electrode active material coated on an electrode base material, the method comprising: obtaining an I peak in parallel direction /I peak in perpendicular direction value of the electrode active material by X-ray diffraction; and calculating an electrode density according to a previously obtained correlation between the electrode density and the I peak in parallel direction /I peak in perpendicular direction value of a same electrode active material wherein the electrode is an anode and the electrode active material is a crystalline carbon-based active material, wherein I peak in parallel direction is an area of an intensity peak when the crystal planes for the electrode active material are arranged parallel to a base plane of the electrode and wherein I peak in perpendicular direction is an area of an intensity peak when the crystal planes of the electrode active material are arranged perpendicular to the base plane of the electrode, wherein in the correlation, the electrode density and the I peak in parallel direction /I peak in perpendicular direction of the electrode active material have a linear relationship, wherein the correlation is obtained in advance by obtaining electrode densities of at least three or more electrodes including a same electrode active material according to Equation 2, measuring an I peak in parallel direction /I peak in perpendicular direction value of the electrode active material of the corresponding electrode by X-ray diffraction, and analyzing a correlation between the electrode density obtained according to Equation 2 and the measured I peak in parallel direction /I peak in perpendicular direction value of the electrode active material, wherein the I peak in parallel direction /I peak in perpendicular direction of the electrode active material is I 004 /I 110: D = M / S × H where D represents an electrode density, S is an electrode area, M is a mass of an electrode active material excluding an electrode base material in an electrode, and H represents a thickness of the electrode active material excluding the electrode base material in the electrode. obtaining an I peak in parallel direction /I peak in perpendicular direction value of the electrode active material by X-ray diffraction; and calculating an electrode density according to a previously obtained correlation between the electrode density and the I peak in parallel direction /I peak in perpendicular direction value of a same electrode active material wherein the electrode is an anode and the electrode active material is a crystalline carbon-based active material, wherein I peak in parallel direction is an area of an intensity peak when the crystal planes for the electrode active material are arranged parallel to a base plane of the electrode and wherein I peak in perpendicular direction is an area of an intensity peak when the crystal planes of the electrode active material are arranged perpendicular to the base plane of the electrode, wherein in the correlation, the electrode density and the I peak in parallel direction /I peak in perpendicular direction of the electrode active material have a linear relationship, wherein the correlation is obtained in advance by obtaining electrode densities of at least three or more electrodes including a same electrode active material according to Equation 2, measuring an I peak in parallel direction /I peak in perpendicular direction value of the electrode active material of the corresponding electrode by X-ray diffraction, and analyzing a correlation between the electrode density obtained according to Equation 2 and the measured I peak in parallel direction /I peak in perpendicular direction value of the electrode active material, wherein the I peak in parallel direction /I peak in perpendicular direction of the electrode active material is I 004 /I 110: D = M / S × H where D represents an electrode density, S is an electrode area, M is a mass of an electrode active material excluding an electrode base material in an electrode, and H represents a thickness of the electrode active material excluding the electrode base material in the electrode. where D represents an electrode density, S is an electrode area, M is a mass of an electrode active material excluding an electrode base material in an electrode, and H represents a thickness of the electrode active material excluding the electrode base material in the electrode.