An objective is to provide a method of manufacturing a semiconductor device, and a semiconductor device manufactured by using the manufacturing method, in which a laser crystallization method is used that is capable of preventing the formation of grain boundaries in TFT channel formation regions, and is capable of preventing conspicuous drops in TFT mobility, reduction in the ON current, and increases in the OFF current, all due to grain boundaries. Depressions and projections with stripe shape or rectangular shape are formed. Continuous wave laser light is then irradiated to a semiconductor film formed on an insulating film along the depressions and projections with stripe shape of the insulating film, or along a longitudinal axis direction or a transverse axis direction of the rectangular shape. Note that although it is most preferable to use continuous wave laser light at this point, pulse wave laser light may also be used.