A method for fabricating a thin-film transistor is provided whereby isolation of transistor devices is realized and the performance and the stability of the product thin-film transistor are improved. The thin-film transistor includes a substrate; a gate electrode laminated on the substrate; a gate insulating layer laminated on the substrate and the gate electrode; a recessed portion provided in the gate insulating layer; a semiconductor layer formed in the recessed portion of the gate insulating layer; and a source electrode and a drain electrode connected to the semiconductor layer at respective positions which are spaced apart from each other.