An electrically heated catalyst comprising: a heat generation element that is adapted to be electrically energized to generate heat; a case that contains said heat generation element therein; a mat that is arranged between said heat generation element and said case, and serves to insulate electricity and at the same time to support said heat generation element; an electrode that is connected to said heat generation element from outside of said case; an insulation part that plugs a gap between said case and said electrode; an electrode chamber that is a space formed around said electrode at an inner side of said case and at an outer side of said heat generation element, and is formed by providing a gap between said electrode and said mat, at each of an upstream side and a downstream side of said electrode; characterized in that the electrically heated catalyst comprises: an inner pipe made of an electrically insulating material and formed into a tubular shape coaxial with said heat generating element, said inner pipe protruding from said mat to an upstream side thereof, a downstream side thereof, and into said electrode chamber; and a partition part that extends through said inner pipe protruding into said electrode chamber at the upstream side of said electrode in a direction of flow of an exhaust gas, in such a manner that the exhaust gas flowing through the interior of said electrode chamber impinges against said partition part; wherein said mat is arranged between said heat generating element and said inner pipe and between said inner pipe and said case, and said partition part is arranged in a manner that it is not in contact with said case, said catalyst carrier and said mat. a heat generation element that is adapted to be electrically energized to generate heat; a case that contains said heat generation element therein; a mat that is arranged between said heat generation element and said case, and serves to insulate electricity and at the same time to support said heat generation element; an electrode that is connected to said heat generation element from outside of said case; an insulation part that plugs a gap between said case and said electrode; an electrode chamber that is a space formed around said electrode at an inner side of said case and at an outer side of said heat generation element, and is formed by providing a gap between said electrode and said mat, at each of an upstream side and a downstream side of said electrode; an inner pipe made of an electrically insulating material and formed into a tubular shape coaxial with said heat generating element, said inner pipe protruding from said mat to an upstream side thereof, a downstream side thereof, and into said electrode chamber; and a partition part that extends through said inner pipe protruding into said electrode chamber at the upstream side of said electrode in a direction of flow of an exhaust gas, in such a manner that the exhaust gas flowing through the interior of said electrode chamber impinges against said partition part; wherein said mat is arranged between said heat generating element and said inner pipe and between said inner pipe and said case, and said partition part is arranged in a manner that it is not in contact with said case, said catalyst carrier and said mat.