PROBLEM TO BE SOLVED: To manufacture a thin film transistor array which has less variation in device characteristics in an effective display area of a thin film transistor array with good efficiency.SOLUTION: In a thin film transistor array which has an effective display area at least including an insulation substrate, a gate electrode, a gate insulation layer, a source electrode, a drain electrode and a first semiconductor layer, a plurality of the first semiconductor layers are formed on the insulation substrate in a stripe shape so as to straddle a plurality of thin film transistors. The thin film transistor array includes a plurality of second semiconductor layers provided outside the effective display area.
