To provide a method for producing a fuel oil for a low-pollution, lead-free, high-octane number gasoline engine, providing excellent running performance of a car.

The method for producing the fuel oil for the gasoline engine involves preparing the fuel oil for the gasoline engine satisfying the following conditions at least by using a fraction remaining after removing a benzene fraction from a reformed gasoline, a cracked gasoline, an alkylate and an isomerate: (1) the fuel oil comprises 35-50 vol.% fraction having ≥25°C and <75°C boiling point, 25-40 vol.% fraction having ≥75°C and <125°C boiling point, and 10-30 vol.% fraction having ≥125°C and <175°C boiling point; (2) the octane number by a research method of each of the above fractions is ≥80; (3) the exhaust gas index Y represented by formula (I): Y=1.07BZ+0.12TO+0.11EB+0.05XY+0.03C9+A+0.005[100-(BZ+TO+EB+XY+C9+A)] [wherein, BZ is a benzene content; TO is a toluene content; EB is an ethylbenzene content; XY is a xylene content; and C9+A is a content of a ≥9C aromatic components (each is content in the fuel oil expressed in terms of mol.%)] is ≤5; (4) the benzene content is ≤1 vol.% and the sulfur content is ≤40 ppm; and (5) the octane number by the research method is 97-102.