A junctionless vertical gate transistor includes an active pillar vertically protruding from a substrate and including a first impurity region, a second impurity region and a third impurity region sequentially formed over the first impurity region; gate electrodes coupled to sidewalls of the second impurity region; and bit lines arranged in a direction of intersecting with the gate electrodes and each contacting the first impurity region. The first to the third impurity regions include impurities of the same polarity.