A semiconductor device including fin-FETs capable of suppressing both OFF-current resulting from the short channel effect and junction leakage, and a manufacturing method thereof are provided. A semiconductor device comprises: an active region defined to have a crank shape by an STI region formed on a semiconductor substrate, the active region having an upper surface higher than an upper surface of the STI region; a source region and a drain region formed on both ends of the active region, respectively; a channel region formed between the source region and the drain region in the active region; and a gate electrode covering an upper surface and side surfaces of a central portion of the active region including the channel region.