A negatively-chargeable electrophotographic photosensitive member comprising: a cylindrical substrate having a conductive surface, and a photoconductive layer formed of a non-single crystal material containing silicon atoms, wherein; a first lower-part layer and a second lower-part layer are provided in this order from the cylindrical substrate side, between the cylindrical substrate and the photoconductive layer; an upper-part layer (105; 205, 206) formed of a non-single crystal material containing silicon atoms is provided on the photoconductive layer; the first lower-part layer is made up of a non-single crystal material composed chiefly of silicon atoms and further containing an element belonging to Group 13 of the periodic table; the second lower-part layer is made up of a non-single crystal material composed chiefly of silicon atoms; the upper-part layer (105; 205, 206) has a region capable of retaining electrification charges; the first lower-part layer has a layer thickness of from 0.1 μm or more to 10 μm or less; the first lower-part layer has a blocking ability against electrons; the second lower-part layer has a blocking ability against holes; and the product of: i) the content (atom ppm) of the Group 13 element belonging to Group 13 of the periodic table, based on the total number of atoms of constituent elements contained in the first lower-part layer, and ii) the layer thickness of the first lower-part layer is from 8 atom ppm·μm or more to 240 atom ppm·μm or less. a cylindrical substrate having a conductive surface, and a photoconductive layer formed of a non-single crystal material containing silicon atoms, wherein; a first lower-part layer and a second lower-part layer are provided in this order from the cylindrical substrate side, between the cylindrical substrate and the photoconductive layer; an upper-part layer (105; 205, 206) formed of a non-single crystal material containing silicon atoms is provided on the photoconductive layer; the first lower-part layer is made up of a non-single crystal material composed chiefly of silicon atoms and further containing an element belonging to Group 13 of the periodic table; the second lower-part layer is made up of a non-single crystal material composed chiefly of silicon atoms; the upper-part layer (105; 205, 206) has a region capable of retaining electrification charges; the first lower-part layer has a layer thickness of from 0.1 μm or more to 10 μm or less; the first lower-part layer has a blocking ability against electrons; the second lower-part layer has a blocking ability against holes; and the product of: i) the content (atom ppm) of the Group 13 element belonging to Group 13 of the periodic table, based on the total number of atoms of constituent elements contained in the first lower-part layer, and ii) the layer thickness of the first lower-part layer is from 8 atom ppm·μm or more to 240 atom ppm·μm or less. i) the content (atom ppm) of the Group 13 element belonging to Group 13 of the periodic table, based on the total number of atoms of constituent elements contained in the first lower-part layer, and ii) the layer thickness of the first lower-part layer is from 8 atom ppm·μm or more to 240 atom ppm·μm or less.