A semiconductor device includes: a thin film transistor having a gate line (3a), a first insulating film (5), an island-shaped oxide semiconductor layer (7a), a second insulating film (9), a source line (13as), a drain electrode (13ad), and a passivation film; and a terminal portion having a first connecting portion (3c) made of the same conductive film as the gate line, a second connecting portion (13c) made of the same conductive film as the source line and the drain electrode, and a third connecting portion (19c) formed on the second connecting portion. The second connecting portion is in contact with the first connecting portion within a first opening (11c) provided in the first and second insulating films; the third connecting portion (19c) is in contact with the second connecting portion within a second opening (17c) provided in the passivation film; and the second connecting portion (13c) covers end faces of the first and second insulating films within the first opening (11c), but does not cover an end face of the passivation film (15) within the second opening (17c). As a result, the taper shape of a contact hole of the terminal portion can be controlled with a high precision.