A semiconductor device production method includes: forming a semiconductor region including a first region, a second region connecting with the first region and having a width smaller than that of the first region, and a third region connecting with the second region and having a width smaller than that of the second region; forming a gate electrode including a first part crossing the third region and a second part extending from the first part across the first region; forming a side wall insulation film on the gate electrode to cover part of the second region while exposing the remaining part of the second region; implanting a second conductivity type impurity into the first region and the remaining part of the second region; performing heat treatment; removing part of the side wall insulation film, and forming a silicide layer on the first region and the remaining part of the second region.