An electrophotographic photoreceptor for positive charging, comprising: a conductive support; and a single-layer type photosensitive layer disposed on the conductive support, wherein the single-layer type photosensitive layer at least contains a binder resin, a compound having hole transporting ability, and a compound having electron-transporting ability, wherein the binder resin contains a polyarylate resin, and when in density function calculation B3LYP/6-31G (d, p), calculated according to the description, a compound having hole transporting ability with a highest energy level of HOMO among the compounds having hole transporting ability is designated as a compound A, and the energy level of HOMO of the compound A is set to Ah, a compound having electron-transporting ability with a lowest energy level of LUMO among the compounds having electron-transporting ability is designated as a compound B, and the energy level of LUMO of the compound B is set to Bl, and a compound which has a molecular weight of 500 or less and is other than the compound A and the compound B in the single-layer type photosensitive layer is designated as a compound C, and an energy level of HOMO of the compound C is set to Ch and an energy level of LUMO of the compound C is set to Cl, the following Equations,, and are satisfied: Ah − Ch ≥ 0.10 eV B 1 − Ch ≥ 1.18 eV Ch ≤ − 4.9 eV C 1 ≥ − 3.2 eV a conductive support; and a single-layer type photosensitive layer disposed on the conductive support, wherein the single-layer type photosensitive layer at least contains a binder resin, a compound having hole transporting ability, and a compound having electron-transporting ability, wherein the binder resin contains a polyarylate resin, and when in density function calculation B3LYP/6-31G (d, p), calculated according to the description, a compound having hole transporting ability with a highest energy level of HOMO among the compounds having hole transporting ability is designated as a compound A, and the energy level of HOMO of the compound A is set to Ah, a compound having electron-transporting ability with a lowest energy level of LUMO among the compounds having electron-transporting ability is designated as a compound B, and the energy level of LUMO of the compound B is set to Bl, and a compound which has a molecular weight of 500 or less and is other than the compound A and the compound B in the single-layer type photosensitive layer is designated as a compound C, and an energy level of HOMO of the compound C is set to Ch and an energy level of LUMO of the compound C is set to Cl, a compound having hole transporting ability with a highest energy level of HOMO among the compounds having hole transporting ability is designated as a compound A, and the energy level of HOMO of the compound A is set to Ah, a compound having electron-transporting ability with a lowest energy level of LUMO among the compounds having electron-transporting ability is designated as a compound B, and the energy level of LUMO of the compound B is set to Bl, and a compound which has a molecular weight of 500 or less and is other than the compound A and the compound B in the single-layer type photosensitive layer is designated as a compound C, and an energy level of HOMO of the compound C is set to Ch and an energy level of LUMO of the compound C is set to Cl, the following Equations,, and are satisfied: Ah − Ch ≥ 0.10 eV B 1 − Ch ≥ 1.18 eV Ch ≤ − 4.9 eV C 1 ≥ − 3.2 eV