It is an object to suppress a change in a characteristic of a semiconductor device with a removal of a hard mask while making the most of an advantage of a gate electrode formed by using the hard mask. A gate electrode (3) is formed by etching using a hard mask as a mask and the hard mask remains on an upper surface of the gate electrode (3) at a subsequent step. In the meantime, the upper surface of the gate electrode (3) can be therefore prevented from being unnecessarily etched. The hard mask is removed after ion implantation for forming a source-drain region. Consequently, the influence of the removal of the hard mask on a characteristic of a semiconductor device can be suppressed. In that case, moreover, a surface of a side wall (4) is also etched by a thickness of (d) so that an exposure width of an upper surface of the source-drain region is increased. After the removal of the hard mask, it is easy to salicide the gate electrode (3) and to form a contact on the gate electrode (3).