A semiconductor device, comprising: a first conductivity type first semiconductor layer ; a second conductivity type second semiconductor layer provided on the first semiconductor layer ; a first conductivity type third semiconductor layer selectively provided in a surface layer of the second semiconductor layer on the side opposite to that of the first semiconductor layer ; a second conductivity type fourth semiconductor layer selectively provided inside the third semiconductor layer ; a first trench penetrating the third semiconductor layer and fourth semiconductor layer to reach the second semiconductor layer ; a first conductivity type fifth semiconductor layer , selectively provided in a surface layer of the second semiconductor layer on the side opposite to that of the first semiconductor layer , separated from the third semiconductor layer by the first trench; a second trench reaching the second semiconductor layer from the surface of the fifth semiconductor layer on the side opposite to that of the first semiconductor layer ; a first conductivity type sixth semiconductor layer , selectively provided in a surface layer of the second semiconductor layer on the side opposite to that of the first semiconductor layer separated from the fifth semiconductor layer by the second trench ; an emitter electrode conductively connected to the third semiconductor layer , fourth semiconductor layer , and sixth semiconductor layer and electrically isolated from the fifth semiconductor layer ; a collector electrode conductively connected to the first semiconductor layer ; a first gate electrode provided across a first gate insulating film inside the first trench ; and a second gate electrode provided across a second gate insulating film inside the second trench and electrically connected to the emitter electrode , characterized in that the width of the sixth semiconductor layer is less than the width of the third semiconductor layer . a first conductivity type first semiconductor layer ; a second conductivity type second semiconductor layer provided on the first semiconductor layer ; a first conductivity type third semiconductor layer selectively provided in a surface layer of the second semiconductor layer on the side opposite to that of the first semiconductor layer ; a second conductivity type fourth semiconductor layer selectively provided inside the third semiconductor layer ; a first trench penetrating the third semiconductor layer and fourth semiconductor layer to reach the second semiconductor layer ; a first conductivity type fifth semiconductor layer , selectively provided in a surface layer of the second semiconductor layer on the side opposite to that of the first semiconductor layer , separated from the third semiconductor layer by the first trench; a second trench reaching the second semiconductor layer from the surface of the fifth semiconductor layer on the side opposite to that of the first semiconductor layer ; a first conductivity type sixth semiconductor layer , selectively provided in a surface layer of the second semiconductor layer on the side opposite to that of the first semiconductor layer separated from the fifth semiconductor layer by the second trench ; an emitter electrode conductively connected to the third semiconductor layer , fourth semiconductor layer , and sixth semiconductor layer and electrically isolated from the fifth semiconductor layer ; a collector electrode conductively connected to the first semiconductor layer ; a first gate electrode provided across a first gate insulating film inside the first trench ; and a second gate electrode provided across a second gate insulating film inside the second trench and electrically connected to the emitter electrode , characterized in that the width of the sixth semiconductor layer is less than the width of the third semiconductor layer . <EOS>