A chassis structure of an image forming apparatus, the structure comprising: a chassis that houses a component used for an image forming apparatus inside and that includes an opening; a cover member that covers the opening of the chassis ; and a seal member (B) that is provided between the cover member and the chassis and that, when the cover member is attached to the chassis , is compressed and deformed so as to seal a gap between the cover member and the chassis , wherein the cover member includes a bottom section; an outer wall section that rises from an outer circumference of the bottom section; and an inner wall section that is provided inside the outer wall section, and an attached section of the cover member is a section of the bottom section that is between the outer wall section and the inner wall section; an outer molding height (D2) of the seal member (B) that is in contact with the outer wall section of the cover member is greater than a gap (D0) between the chassis and the cover member in a thickness direction of the bottom section, and an inner molding height (D4) of the seal member (B) that is in contact with the inner wall section of the cover member is greater than a gap (D0) between the chassis and the cover member in a thickness direction of the bottom section; and characterized in that : the outer molding height (D2) of the seal member (B) is greater than the inner molding height (D4) of the seal member (B); and the attached section of the cover member to which the seal member is attached is provided with a hole . a chassis that houses a component used for an image forming apparatus inside and that includes an opening; a cover member that covers the opening of the chassis ; and a seal member (B) that is provided between the cover member and the chassis and that, when the cover member is attached to the chassis , is compressed and deformed so as to seal a gap between the cover member and the chassis , wherein the cover member includes a bottom section; an outer wall section that rises from an outer circumference of the bottom section; and an inner wall section that is provided inside the outer wall section, and a bottom section; an outer wall section that rises from an outer circumference of the bottom section; and an inner wall section that is provided inside the outer wall section, and an attached section of the cover member is a section of the bottom section that is between the outer wall section and the inner wall section; an outer molding height (D2) of the seal member (B) that is in contact with the outer wall section of the cover member is greater than a gap (D0) between the chassis and the cover member in a thickness direction of the bottom section, and an inner molding height (D4) of the seal member (B) that is in contact with the inner wall section of the cover member is greater than a gap (D0) between the chassis and the cover member in a thickness direction of the bottom section; and characterized in that : the outer molding height (D2) of the seal member (B) is greater than the inner molding height (D4) of the seal member (B); and the attached section of the cover member to which the seal member is attached is provided with a hole . the outer molding height (D2) of the seal member (B) is greater than the inner molding height (D4) of the seal member (B); and the attached section of the cover member to which the seal member is attached is provided with a hole . <EOS>