An IGBT comprising: a drift region of a first conductive type; a body region of a second conductive type formed on an upper surface of the drift region and making contact with the drift region; an emitter region of the first conductive type formed in an upper surface of the body region and making contact with the body region; a trench gate electrode passing through the body region from the upper surface of the body region to a lower surface of the body region, a gate insulator film being provided between a side face of the trench gate electrode and a side face of the emitter region; and a floating semiconductor region of the first conductive type, the floating semiconductor region being formed within the body region of the second conductive type and being isolated from both the emitter region of the first conductive type and the drift region of the first conductive type by the body region of the second conductive type; a second electrode (62, 63, 66) extending from the upper surface of the body region toward the drift region and reaching at least the floating semiconductor region of the first conductive type, the second electrode (62, 63, 66) being isolated from the floating semiconductor region by an insulator film (64, 65, 68) being provided in contact with the second electrode (62, 63, 66) and provided between the second electrode (62, 63, 66) and the floating semiconductor region, the insulator film (64, 65, 68) further being provided between the second electrode (62, 63, 66) and the part of the body region, which extends from the emitter region to the floating semiconductor region in parallel to the side face of the trench gate electrode and which separates the floating semiconductor region and the emitter region, the second electrode (62, 63, 66) not making contact with the emitter region and the insulator film (64, 65, 68) being spaced from the emitter region; wherein the second electrode (62, 63, 66) and the trench gate electrode are electrically connected. a drift region of a first conductive type; a body region of a second conductive type formed on an upper surface of the drift region and making contact with the drift region; an emitter region of the first conductive type formed in an upper surface of the body region and making contact with the body region; a trench gate electrode passing through the body region from the upper surface of the body region to a lower surface of the body region, a gate insulator film being provided between a side face of the trench gate electrode and a side face of the emitter region; and a floating semiconductor region of the first conductive type, the floating semiconductor region being formed within the body region of the second conductive type and being isolated from both the emitter region of the first conductive type and the drift region of the first conductive type by the body region of the second conductive type; a second electrode (62, 63, 66) extending from the upper surface of the body region toward the drift region and reaching at least the floating semiconductor region of the first conductive type, the second electrode (62, 63, 66) being isolated from the floating semiconductor region by an insulator film (64, 65, 68) being provided in contact with the second electrode (62, 63, 66) and provided between the second electrode (62, 63, 66) and the floating semiconductor region, the insulator film (64, 65, 68) further being provided between the second electrode (62, 63, 66) and the part of the body region, which extends from the emitter region to the floating semiconductor region in parallel to the side face of the trench gate electrode and which separates the floating semiconductor region and the emitter region, the second electrode (62, 63, 66) not making contact with the emitter region and the insulator film (64, 65, 68) being spaced from the emitter region; wherein the second electrode (62, 63, 66) and the trench gate electrode are electrically connected.