An image forming apparatus is configured to electro-photographically form an image and includes a main body frame which includes a side wall, an outer cover which covers an outer face of the main body frame, a high-voltage board which includes a high-voltage generator circuit configured to generate a high voltage and supply an electric power to a device requiring a high-voltage power source, and a main board which includes a main control circuit configured to perform a control on an image forming process of the image forming apparatus. In a side region which is formed by the side wall of the main body frame and the outer cover, the high-voltage board and the main board are disposed along the side wall to overlap with each other at least partially, and the high-voltage board is disposed on an outer side relative to the main board.