The invention provides an LDMOS transistor of which the time-dependent degrading of the performance due to the trapping of hot electrons in the gate insulation film is decreased. A body layer is disposed in a surface portion of an N−− type semiconductor layer. A source layer including an N− type layer is disposed in a surface portion of the body layer. An N− type drift layer is formed in a surface portion of the N−− type semiconductor layer. This drift layer includes a first region having a first N type impurity concentration peak region and a second region having a second N type impurity concentration peak region that is positioned deeper than the first N type impurity concentration peak region, the second region adjoining this first region. An N+ type drain layer is formed in a surface portion of the second region.