A polysilicon thin film transistor device includes a gate metal pattern including a gate electrode and a gate line formed on a substrate, the gate metal pattern having a stepped portion, a gate insulating film formed on the gate metal pattern, a polysilicon semiconductor layer formed on the gate insulating film, the polysilicon semiconductor layer including an active region, lightly doped drain regions, a source region, and a drain region, a source electrode connected to the source region and a drain electrode connected to the drain region on the polysilicon semiconductor layer, and a pixel electrode connected with the drain electrode.