A liquid-cooled engine provided with cooling means for cooling an area surrounding a combustion chamber using a cooling liquid cooled by a radiator and caused to flow through a cooling passage. The cooling passage is embedded inside a cylinder block and a cylinder head. The cooling passage is formed in a continuous fashion such that the cooling liquid is introduced from the radiator to cool an area surrounding the combustion chamber, and thereafter returns to the radiator by looping around an area surrounding an exhaust valve for opening and closing an exhaust port of the combustion chamber.