The aim is to reduce 3-chloropropanediol and 3-chloropropanediol fatty acid esters, which are chloropropanols, and glycidol fatty acid esters, which are a formative substance thereof, from oils. Chloropropanols and glycidol fatty acid esters, which are a formative substance thereof, can be reduced in glyceride oils by treating decolorized and deodorized glyceride oils with a silica gel and/or a basic activated carbon, by mixing the glyceride oils with an organic acid aqueous solution and dehydrating under reduced pressure at 50°C to 180°C, or by mixing the glyceride oils with a solvent and then removing the solvent or the low melting point fractions of the solvent and the glyceride oils. Additionally, the glycidol fatty acid esters can be reduced in glyceride oils by bringing the decolorized and deodorized glyceride oils and an acid into contact.