To provide an EGR passage structure enabling stable EGR introduction with less influences of pulsation while actualizing a smaller space, a lower cost and a lighter weight.

An EGR passage 6 linking an exhaust pipe 2a of an exhaust manifold 2 with an intake pipe 4a of an intake manifold 4 is formed in a cylinder head 1. The EGR passage 6 consists of a take-in passage 6a communicated with the exhaust pipe 2a, a passage expansion part 6b having a larger cross section area than the take-in passage 6a, and an exhaust passage 6c having a smaller cross section area than the passage expansion part 6b. The passage expansion part 6b out of them is formed inside a cylinder head 1 across a wall 9 from a water jacket 8. An inflow pipe 8a and an outflow pipe 8b for cooling water to flow into and out of the water jacket 8, respectively, are arranged coming across an internal space of the passage expansion part 6b.