A charging device includes a charging member disposed opposite to a surface of an image carrier. The image carrier is charged by applying a voltage to the charging member, and the charging member includes a substrate and a resistor layer thereon. The resistor layer is disposed with two spacers contacting with the image carrier, so that a gap is created between the image carrier and the resistor layer between the two spacers, wherein width variation of the gap with time is prevented. The end portions of the resistor layer of the charging member protrude above the resistor layer between them, and the spacers are constituted by protrudent fractions of the end portions of the resistor layer.