A casing for electronic ballast, in which a PCB assembly is received, may include: a top wall; a bottom wall opposite to the top wall; two opposite side walls extending integrally between the top wall and bottom wall; and two opposite end walls extending integrally from the top wall, wherein the top wall, bottom wall, side walls and end walls are formed integrally, the top wall, bottom wall and side walls define openings at both ends of the casing in a lengthwise direction of the casing, the end walls are arranged to be pivotable relative to the top wall so as to close the openings formed by the top wall, bottom wall and side walls.