A capacitance type sensor comprising a first electrode (10a, 10b, 10c, 30) and a second electrode (20a, 20b, 20c, 20d) disposed opposite to and out of contact with each other with the gap between them changing with a change in detected amount, and a signal processing unit (4) for calculating a detected amount based on a capacitance formed between the first and second electrodes, wherein the first electrode is provided with a portion (12a, 14a) of which area opposite to the second electrode increases and a portion (12b, 14b) of which area opposite to the second electrode decreases according to a positional error produced in directions (x, y) parallel to the first electrode, these portions having the same area.