The present invention provides a semiconductor device which suppresses a short circuit and a leakage current between a semiconductor film and a gate electrode generated by a break or thin thickness of a gate insulating film in an end portion of a channel region of the semiconductor film, and the manufacturing method of the semiconductor device. Plural thin film transistors which each have semiconductor film provided over a substrate continuously, conductive films provided over the semiconductor film through a gate insulating film, source and drain regions provided in the semiconductor film which are not overlapped with the conductive films, and channel regions provided in the semiconductor film existing under the conductive films and between the source and drain regions. And impurity regions provided in the semiconductor film which is not overlapped with the conductive film and provided adjacent to the source and drain regions. Further, the conductive films are provided over the channel regions and regions of the semiconductor film which are provided adjacent to the channel regions.