In the invention, a low concentration impurity region is formed between a channel formation region and a source region or a drain region in a semiconductor layer and covered with a gate electrode layer in a thin film transistor The semiconductor layer is doped obliquely to the surface thereof using the gate electrode layer as a mask to form the low concentration impurity region. The semiconductor layer is formed to have an impurity region including an impurity element for imparting one conductivity which is different from conductivity of the thin film transistor, thereby being able to minutely control the properties of the thin film transistor.