A method for improving productivity when manufacturing a semiconductor device. A lower electrode, insulating films, an upper electrode and insulating films are formed on a semiconductor substrate in a sensor region. A cavity is formed between the insulator films above the lower electrode. The lower electrode, insulating film, the cavity and insulating film, and an upper electrode form a variable capacity sensor. The cavity is formed by etching a sacrificial pattern between the insulation films by way of a hole formed in a pair of insulation films. Other than in the above sensor region, a dummy lower electrode and four insulating films are formed on the TEG region on the semiconductor substrate; and a dummy cavity is formed between a pair of insulation films above the lower electrode however no conductive layer on the same layer as the upper electrode is formed on the dummy cavity.