An electrically heated catalyst comprising: a heat generating element which generates heat by applying electricity; a case which accommodates the heat generating element; and a mat which is provided between the case and the heat generating element and which supports the heat generating element; wherein the case includes a tubular portion which is provided on an outer circumferential side of the heat generating element and which is formed in parallel to a central axis of the heat generating element, an inlet portion which is provided on the upstream side from the tubular portion and which has an inner diameter smaller than that of the tubular portion, an inclined portion which connects the tubular portion and the inlet portion and which has cross-sectional areas that are increased on the more downstream side, and an introducing portion which extends from a connected portion between the inlet portion and the inclined portion toward inside of the case; characterized in that: the electrically heated catalyst further comprises an inner tube which is interposed by the mat, which protrudes from the mat toward an upstream side and a downstream side of a flow of exhaust gas, and which insulates the electricity; the introducing portion is curved so that a center of curvature is positioned outside the introducing portion; the inner tube includes a tubular portion which is provided on an outer circumferential side of the heat generating element and which is formed in parallel to a central axis of the heat generating element, and an inclined portion which is provided on the upstream side from the tubular portion and which has inner diameters that are decreased on the more upstream side; and the inclined portion of the inner tube is curved. a heat generating element which generates heat by applying electricity; a case which accommodates the heat generating element; and a mat which is provided between the case and the heat generating element and which supports the heat generating element; wherein the case includes a tubular portion which is provided on an outer circumferential side of the heat generating element and which is formed in parallel to a central axis of the heat generating element, an inlet portion which is provided on the upstream side from the tubular portion and which has an inner diameter smaller than that of the tubular portion, an inclined portion which connects the tubular portion and the inlet portion and which has cross-sectional areas that are increased on the more downstream side, and an introducing portion which extends from a connected portion between the inlet portion and the inclined portion toward inside of the case; characterized in that: the electrically heated catalyst further comprises an inner tube which is interposed by the mat, which protrudes from the mat toward an upstream side and a downstream side of a flow of exhaust gas, and which insulates the electricity; the introducing portion is curved so that a center of curvature is positioned outside the introducing portion; the inner tube includes a tubular portion which is provided on an outer circumferential side of the heat generating element and which is formed in parallel to a central axis of the heat generating element, and an inclined portion which is provided on the upstream side from the tubular portion and which has inner diameters that are decreased on the more upstream side; and the inclined portion of the inner tube is curved. the electrically heated catalyst further comprises an inner tube which is interposed by the mat, which protrudes from the mat toward an upstream side and a downstream side of a flow of exhaust gas, and which insulates the electricity; the introducing portion is curved so that a center of curvature is positioned outside the introducing portion; the inner tube includes a tubular portion which is provided on an outer circumferential side of the heat generating element and which is formed in parallel to a central axis of the heat generating element, and an inclined portion which is provided on the upstream side from the tubular portion and which has inner diameters that are decreased on the more upstream side; and the inclined portion of the inner tube is curved.