Process for the quantitative preparation of esters, with a high yield, which comprises reacting an aldehyde or ketone compound and an acid halide compound in a one pot reaction in the presence of at least one compound represented by the following formulae: RMgX   (I); RMgX/CuX   (II); and RLi or R(CuLi)½  (III); in which R represents a hydrocarbon group, and X represents a halogen atom. Production processes of a resist material and a semiconductor device are also disclosed.