A mounting structure for a shielding shell for at least partly covering a connector housing of a device connector to be connected to a case of a device, comprising: a metal plate integrally provided to the connector housing and adapted to attach and fix the connector housing to the case of the device by being fastened to the case of the device by at least one mounting bolt; a first shielding shell including a first mounting portion and adapted to at least partly cover one side of the connector housing; and a second shielding shell including a second mounting portion and adapted to at least partly cover at least one other side of the connector housing; wherein the first and second mounting portions (76, 72) are in the form of plates extending along the metal plate and fastened together to the case of the device by the mounting bolt together with the metal plate while being placed one over the other; characterized in that the first shielding shell includes a front wall which at least partly covers the connector housing from front; the second shielding shell includes a ceiling wall which at least partly covers the connector housing from above and a pair of side walls which are adjacent to the ceiling wall and at least partly cover the connector housing from lateral sides; the first and second shielding shells (70A, 70B) are integrally formed by, after a metal flat plate is brought into a specified shape particularly by a press, bending a boundary part between the front wall and the ceiling wall; the front wall includes an extended wall projecting sideways from the side wall; the first mounting portion projects backward by bending a part of the extended wall toward the ceiling wall; and/or the second mounting portion projects sideways by bending a part of the side wall toward the ceiling wall. a metal plate integrally provided to the connector housing and adapted to attach and fix the connector housing to the case of the device by being fastened to the case of the device by at least one mounting bolt; a first shielding shell including a first mounting portion and adapted to at least partly cover one side of the connector housing; and a second shielding shell including a second mounting portion and adapted to at least partly cover at least one other side of the connector housing; wherein the first and second mounting portions (76, 72) are in the form of plates extending along the metal plate and fastened together to the case of the device by the mounting bolt together with the metal plate while being placed one over the other; characterized in that the first shielding shell includes a front wall which at least partly covers the connector housing from front; the second shielding shell includes a ceiling wall which at least partly covers the connector housing from above and a pair of side walls which are adjacent to the ceiling wall and at least partly cover the connector housing from lateral sides; the first and second shielding shells (70A, 70B) are integrally formed by, after a metal flat plate is brought into a specified shape particularly by a press, bending a boundary part between the front wall and the ceiling wall; the front wall includes an extended wall projecting sideways from the side wall; the first mounting portion projects backward by bending a part of the extended wall toward the ceiling wall; and/or the second mounting portion projects sideways by bending a part of the side wall toward the ceiling wall.