The present invention is configured such that: a cylinder block includes an introducing portion provided at a first side of a cylinder row, cooling liquid being introduced through the introducing portion to a water jacket, a restrictor portion provided in a vicinity of the introducing portion and configured to restrict the cooling liquid, introduced through the introducing portion, from flowing to an intake-side portion of the water jacket, and a discharging portion provided at a middle portion of the cylinder row at an intake side, the cooling liquid being discharged from the water jacket through the discharging portion; and an exhaust-side portion of the water jacket is formed such that a passage cross-sectional area of a cylinder axis direction upper side of the exhaust-side portion is larger than the passage cross-sectional area of a cylinder axis direction lower side of the exhaust-side portion.