Electricity is suppressed from flowing to a case (2) of an electric heating type catalyst (1). The electric heating type catalyst (1) is provided with a heat generation element (4) to be electrically energized to generate heat, the case (2) in which the heat generation element (4) is received, and a mat (3) inserted between the heat generation element (4) and the case (2) for insulating electricity, wherein the case (2) is formed into double pipes (24) at an upstream side and downstream side of the heat generation element (4), respectively, and an inner pipe (28) of each of the double pipes (24) is formed such that it is in contact at an upstream side or downstream side one end (25) thereof with an outer pipe (27) of each double pipe (24), with a gap being formed between the inner pipe (28) and the outer pipe (27) of each double pipe (24) at an upstream side or downstream side other end (26) of the inner pipe (28), and an insulating layer (6) for insulating electricity is provided on a surface of the case (2) from the mat (3) to the other end (26) including a range surrounded by the outer pipe (27) and the inner pipe (28) of each double pipe (24).