The purpose of the present invention is to provide a thin-film transistor which can have both an excellent ON characteristic and an excellent OFF characteristic, and electric characteristics of which will be symmetrical even when exchanging the source electrode and drain electrode thereof. The thin-film transistor is provided with: a substrate (100); a gate electrode (110); a gate insulation layer (120); a crystalline silicon layer (131) formed on the gate insulation layer (120) that is above the gate electrode (110); an amorphous silicon layer (131) that is formed on the gate insulation layer (120) at both sides of the crystalline silicon layer (131), and the film thickness of which is smaller than the film thickness of the crystalline silicon layer (131); a channel protection layer (140) that is formed on the crystalline silicon layer (131); and a source electrode (171) and a drain electrode (172).