An AC adapter including a synthetic resin case (34), and a switching regulator circuit assembly (40) having an AC input terminal (43) and a DC output terminal (44), the switching regulator circuit assembly (40) being housed in the synthetic resin case (34), the AC adapter being characterized in that a metallic sheet (70) for heat radiation is separated from a resin name plate (71) and the metallic sheet (70) is attached to a surface of the case (34) except for a portion for the AC input (43) terminal.
