A Δ Σ type AD converter includes a local D/A converter having a SC integrator which is constructed by an analog switch operated at the first and second timings of an input (1), an analog switch operated at the first and second timings of an input (2), an analog switch operated at the first and second timings without selection of the input, a capacitor charged and discharged by these analog switches and an operational amplifier (21), a comparator (22), a D-type flip-flop (28), a switch (29) and reference voltage sources (30, 31).