A method for evaluating a coating state of a protein adsorbent, which is a cell adhesion factor, or an adsorption state of a protein, the method comprising: providing a substrate 1 having a coating layer containing the protein adsorbent and a fluorescent dye formed on at least one surface of a polymer substrate, irradiating the substrate 1 with light at the excitation wavelength of the dye and detecting a color development state 1 of the substrate 1; providing a substrate 2 having a coating layer containing the protein adsorbent and the fluorescent dye and a coating layer containing a protein detection reagent which is able to conjugate with the protein and which absorbs light at the excitation wavelength of the fluorescent dye, sequentially formed on at least one surface of a polymer substrate, irradiating the substrate 2 with light at the excitation wavelength of the dye and detecting a color development state 2 of the substrate 2; providing a substrate 3 having a coating layer containing the protein adsorbent and the fluorescent dye formed on at least one surface of a polymer substrate, introducing a sample containing a protein onto the substrate 3 to obtain a substrate 4, irradiating the substrate 4 with light at the excitation wavelength of the dye and detecting a color development state 3 of the substrate 4; providing a substrate 5 having a coating layer containing the protein adsorbent and the fluorescent dye formed on at least one surface of a polymer substrate, introducing a sample containing a protein onto the substrate 5 to obtain a substrate 6, introducing a protein detection reagent onto the substrate 6 to obtain a substrate 7, and irradiating the substrate 7 with light at the excitation wavelength of the dye and detecting a color development state 4 of the substrate 7; and comparing the color development state 4 with the color development state 1, 2, or 3 to evaluate a coating state of the protein adsorbent or an adsorption state of the protein, wherein in a case where light absorption of the fluorescent dye is suppressed in the color development state 4 as compared with the color development state 1, 2, or 3, it is evaluated that the protein is adsorbed on the polymer substrate or the protein adsorbent is coated on the polymer substrate. providing a substrate 1 having a coating layer containing the protein adsorbent and a fluorescent dye formed on at least one surface of a polymer substrate, irradiating the substrate 1 with light at the excitation wavelength of the dye and detecting a color development state 1 of the substrate 1; providing a substrate 2 having a coating layer containing the protein adsorbent and the fluorescent dye and a coating layer containing a protein detection reagent which is able to conjugate with the protein and which absorbs light at the excitation wavelength of the fluorescent dye, sequentially formed on at least one surface of a polymer substrate, irradiating the substrate 2 with light at the excitation wavelength of the dye and detecting a color development state 2 of the substrate 2; providing a substrate 3 having a coating layer containing the protein adsorbent and the fluorescent dye formed on at least one surface of a polymer substrate, introducing a sample containing a protein onto the substrate 3 to obtain a substrate 4, irradiating the substrate 4 with light at the excitation wavelength of the dye and detecting a color development state 3 of the substrate 4; providing a substrate 5 having a coating layer containing the protein adsorbent and the fluorescent dye formed on at least one surface of a polymer substrate, introducing a sample containing a protein onto the substrate 5 to obtain a substrate 6, introducing a protein detection reagent onto the substrate 6 to obtain a substrate 7, and irradiating the substrate 7 with light at the excitation wavelength of the dye and detecting a color development state 4 of the substrate 7; and comparing the color development state 4 with the color development state 1, 2, or 3 to evaluate a coating state of the protein adsorbent or an adsorption state of the protein, wherein in a case where light absorption of the fluorescent dye is suppressed in the color development state 4 as compared with the color development state 1, 2, or 3, it is evaluated that the protein is adsorbed on the polymer substrate or the protein adsorbent is coated on the polymer substrate.