A display device includes: a display panel substrate which includes pixel circuits disposed in rows and columns; COF substrates connected to the display panel substrate; gate driver ICs for display driving, which are mounted on the display panel substrate or on the COF substrates, and each of which includes a shift register; printed circuit boards which are connected to the COF substrates, and each of which includes one or more lines which cascade the gate driver ICs; and a control unit configured to supply a predetermined signal to a cascade input terminal of a gate driver IC located most upstream of the cascade, and monitor a signal from a cascade output terminal of at least one gate driver IC located downstream of the gate driver IC located most upstream.