INTAKE MANIFOLD AND INTAKE DEVICE

An intake manifold M includes: a surge tank , formed in an elongated tubular shape in a direction of a predetermined axis S; branch pipes , extending from the surge tank; an upstream tubular part , continuous on an upstream side of the surge tank; an opening part , open at an upstream end of the upstream tubular part; a flange part , formed around the opening part; an annular seal groove , formed at the flange part around the opening part; and fastening parts , formed at the flange part around the annular seal groove to fasten a throttle unit. A groove width of the annular seal groove is formed to decrease in the vicinity of the fastening part.