A urethane rubber cleaning blade for an electrophotographic apparatus, configured to come into contact with a member to be cleaned and clean a surface of the member to be cleaned, wherein the urethane rubber has an isocyanurate group, a surface C of a contact portion of the cleaning blade that comes into contact with the member to be cleaned has a Young's modulus (Yo) of 0.098 GPa or more and 3.92 GPa or less, wherein the Young's modulus is measured with a microindentation hardness tester in a load-unload test as described in description paragraph 118, the ratio (Y 50 /Y 0) of the Young's modulus (Yso) of an internal portion of the cleaning blade 50 μm spaced apart from the surface C to the Young's modulus (Yo) is 0.5 or less, the Young's modulus decreases from the surface of the contact portion to an internal portion of the cleaning blade 20 μm spaced apart from the surface C and from the internal portion of the cleaning blade 20 μm spaced apart from the surface C to the internal portion of the cleaning blade 50 μm spaced apart from the surface C, by a corresponding decrease of the isocyanurate group concentration, and the average rate of change in Young's modulus [{(Y 0 - Y 20)/Y 0}/(20 - 0)] from the surface C to the internal portion of the cleaning blade 20 μm spaced apart from the surface C is greater than or equal to the average rate of change in Young's modulus [{(Y 20 - Y 50)/Y 0}/(50 - 20)] from the internal portion of the cleaning blade 20 μm spaced apart from the surface C to the internal portion of the cleaning blade 50 μm spaced apart from the surface C, wherein Y 0 denotes the Young's modulus of the surface C, and Y 20 and Y 50 denote the Young's modulus of the internal portion of the cleaning blade 20 μm and 50 μm spaced apart from the surface C, respectively. the urethane rubber has an isocyanurate group, a surface C of a contact portion of the cleaning blade that comes into contact with the member to be cleaned has a Young's modulus (Yo) of 0.098 GPa or more and 3.92 GPa or less, wherein the Young's modulus is measured with a microindentation hardness tester in a load-unload test as described in description paragraph 118, the ratio (Y 50 /Y 0) of the Young's modulus (Yso) of an internal portion of the cleaning blade 50 μm spaced apart from the surface C to the Young's modulus (Yo) is 0.5 or less, the Young's modulus decreases from the surface of the contact portion to an internal portion of the cleaning blade 20 μm spaced apart from the surface C and from the internal portion of the cleaning blade 20 μm spaced apart from the surface C to the internal portion of the cleaning blade 50 μm spaced apart from the surface C, by a corresponding decrease of the isocyanurate group concentration, and the average rate of change in Young's modulus [{(Y 0 - Y 20)/Y 0}/(20 - 0)] from the surface C to the internal portion of the cleaning blade 20 μm spaced apart from the surface C is greater than or equal to the average rate of change in Young's modulus [{(Y 20 - Y 50)/Y 0}/(50 - 20)] from the internal portion of the cleaning blade 20 μm spaced apart from the surface C to the internal portion of the cleaning blade 50 μm spaced apart from the surface C, wherein Y 0 denotes the Young's modulus of the surface C, and Y 20 and Y 50 denote the Young's modulus of the internal portion of the cleaning blade 20 μm and 50 μm spaced apart from the surface C, respectively.