Patent ID: 8647583

Claim:
An electric heating type catalyst comprising: a heat generation element that is electrically energized to generate heat; a case that receives said heat generation element therein; and a mat that is inserted between said heat generation element and said case for insulating electricity; wherein said case is formed into a double pipe at each of an upstream side and a downstream side of said heat generation element, respectively; at the upstream side of said heat generation element, an inner pipe of said double pipe is in contact at a downstream side end thereof with an outer pipe of said double pipe, with a gap being formed between the inner pipe and the outer pipe of said double pipe at an upstream side end of the inner pipe, and at the downstream side of said heat generation element, an inner pipe of said double pipe is in contact at an upstream side end thereof with an outer pipe of said double pipe, with a gap being formed between the inner pipe and the outer pipe of said double pipe at downstream side end of the inner pipe; and an insulating layer for insulating electricity is provided on a surface of said case which extends from said mat to the other end of said inner pipe including a range surrounded by the outer pipe and the inner pipe of said double pipe.