An exhaust manifold has a structure such that an end portion of a collecting section where pipes connected to respective cylinders of an engine are collected is connected to an exhaust pipe via a joint tube member. The joint tube member is constituted by an upper joint portion and a lower joint portion, and cut-out grooves are formed on both joining portions of the upper joint portion or the lower joint portion. With the cut-out grooves, a partition plate is engaged to be positioned, and in this state, the partition plate is fixed to the upper joint portion or the lower joint portion.