In a process for manufacturing an oxide-system dielectric thin film using a raw material compound in which a metal atom is coupled with an organic group through oxygen atoms by the CVD method. A vapor of organic solvent having a boiling point less than 100.degree. C. contacts to the raw material compound at least in one of processes for vaporizing or transporting said raw material compound. The raw material compound of oxide-system dielectric thin film can be vaporized stably and transported to the reactor at a low temperature than before. Therefore, a composition can be controlled homogeneously and an oxide-system dielectric thin film having a good performance can be manufactured.