A TFT includes a supporting substrate, a gate electrode formed on the supporting substrate, a gate insulation film formed on the substrate so as to cover the gate electrode, a first semiconductor layer formed across from the gate electrode with respect to the gate insulation film, a second semiconductor layer formed on the first semiconductor layer, and having a first thickness and a second thickness which is greater than the first thickness, an ohmic contact layer formed on the second semiconductor layer, and a source electrode and a drain electrode formed on the ohmic contact layer, spacing apart with each other.