An assembly comprising an HDMI connector (1; 10, 20; 30, 40; 810, 820; 910, 920) and a mounted substrate, said HDMI connector comprising: a plurality of signal pins (11; 110, 210; 310, 410; 811, 821; 911, 921) that are connected to a wiring pattern on the mounted substrate and that transmit a signal to an inside and an outside of any apparatus, the mounted substrate having an end disposed in the apparatus; a shell (13; 140, 240; 340, 440; 813, 823; 913, 923) that is formed of an electric conductor and covers the signal pin in a region in which the signal pin stretches toward the mounted substrate; and grounding parts (16a-g) between the shell and the mounted substrate that operate to ground the shell to ground potential on the mounted substrate, wherein the shell is grounded to the ground potential by the grounding parts at a plurality of grounding locations on the mounted substrate, wherein a subset of the plurality of the signal pins transmits a differential signal, characterized in that the grounding locations include, with respect to a region corresponding to a location in which the signal pins and the wiring pattern are connected, a first partial region in which the wiring pattern that corresponds to the plurality of signal pins transmitting the differential signal is led out in a direction (y) away from the connector on the mounted substrate, and a second partial region in which the wiring pattern that corresponds to the plurality of signal pins not transmitting the differential signal is led back in a direction opposite to that direction, wherein the plurality of grounding locations of the shell includes locations corresponding to grounding parts (16c, 16d, 16e) sandwiching a region corresponding to a location in which the part of the plurality of the signal pins that transmits the differential signal and the wiring pattern are connected, and wherein a grounding part provided in a location corresponding to the signal pins for transmitting differential signals is larger than each grounding area of grounding parts (16c, 16d, 16e) in the first partial region. a plurality of signal pins (11; 110, 210; 310, 410; 811, 821; 911, 921) that are connected to a wiring pattern on the mounted substrate and that transmit a signal to an inside and an outside of any apparatus, the mounted substrate having an end disposed in the apparatus; a shell (13; 140, 240; 340, 440; 813, 823; 913, 923) that is formed of an electric conductor and covers the signal pin in a region in which the signal pin stretches toward the mounted substrate; and grounding parts (16a-g) between the shell and the mounted substrate that operate to ground the shell to ground potential on the mounted substrate, wherein the shell is grounded to the ground potential by the grounding parts at a plurality of grounding locations on the mounted substrate, wherein a subset of the plurality of the signal pins transmits a differential signal, characterized in that the grounding locations include, with respect to a region corresponding to a location in which the signal pins and the wiring pattern are connected, a first partial region in which the wiring pattern that corresponds to the plurality of signal pins transmitting the differential signal is led out in a direction (y) away from the connector on the mounted substrate, and a second partial region in which the wiring pattern that corresponds to the plurality of signal pins not transmitting the differential signal is led back in a direction opposite to that direction, wherein the plurality of grounding locations of the shell includes locations corresponding to grounding parts (16c, 16d, 16e) sandwiching a region corresponding to a location in which the part of the plurality of the signal pins that transmits the differential signal and the wiring pattern are connected, and wherein a grounding part provided in a location corresponding to the signal pins for transmitting differential signals is larger than each grounding area of grounding parts (16c, 16d, 16e) in the first partial region.