A semiconductor element is provided, comprising a first semiconductor layer of the first conduction type; and a pillar layer including first semiconductor pillars of the first conduction type and second semiconductor pillars of the second conduction type arranged periodically and alternately on the first semiconductor layer. A semiconductor base layer of the second conduction type is formed on the upper surface of the pillar layer, And a second semiconductor layer of the first conduction type is formed on the upper surface of the semiconductor base layer. A control electrode of the trench gate type is formed in a trench, which is formed in depth through the semiconductor base layer to the first semiconductor pillar. The control electrode is tapered such that the width thereof decreases with the distance from a second main electrode toward a first main electrode and the tip thereof locates almost at the center of the first semiconductor pillar.