An image forming apparatus includes an image forming unit for forming an image; a first electrical substrate having an electric circuit for electric power supply to the image forming unit; a second electrical substrate disposed above the first electrical substrate and having an electric circuit for operating the image forming unit; an opening formed above the first electrical substrate in fluid communication with ambient air; and a partition member for partitioning the first electrical substrate and the second electrical substrate and for forming an air flow path from the first electrical substrate to the opening.