A process produces a 2-benzoyloxyacetaldehyde derivative represented by following Formula (3): ##STR00001## wherein R.sup.1 and R.sup.2 may be the same as or different from each other and are each a hydrocarbon group, wherein R.sup.1 and R.sup.2 may be combined to form a ring with the adjacent oxygen-carbon-oxygen bond, and wherein the benzene ring in the formula may be substituted, by allowing a halogenated acetaldehyde acetal derivative represented by following Formula (1): ##STR00002## wherein R.sup.1 and R.sup.2 are as defined above; and X represents a halogen atom, to react with a benzoate represented by following Formula (2): ##STR00003## wherein M represents an alkali metal atom and wherein the benzene ring in the formula may be substituted, in the presence of an alkali-metal halide.