A gas introducing structure of an intake path includes a gas introducing path introducing a gas into an intake airflow in the intake path of an internal combustion engine, wherein an inner peripheral surface of the gas introducing path is made of a bottom surface appearing as a straight line at a lower side of a perpendicular cross section of the inner peripheral surface and a curved wall surface appearing as a convex curved line, connecting with each end of the straight line at an angle, at an upper side of the perpendicular cross section of the inner peripheral surface.