In a process for fabricating a thin-film transistor in which a gate electrode 4 is to be formed on a substrate 1, the process has the steps of forming the gate electrode 4 on the substrate 1, forming a metal oxide layer 7 in such a way as to cover the gate electrode 4, forming a source electrode 6 and a drain electrode 5, and carrying out annealing in an inert gas to change part of the metal oxide layer 7 into a channel region.