An analog-digital converter according to the present invention includes an input polarity switching unit, an integrator that integrates an input signal, an integrator output adjusting circuit that adjusts an output voltage of the integrator, a window comparator, and a controller that controls the input polarity switching unit, the integrator output adjusting circuit, and the window comparator, and generates a digital signal. When the output voltage of the integrator reaches a first reference voltage, the controller resets reference voltage of a high-voltage side comparator to a second reference voltage. Further, when the output voltage of the integrator reaches a third reference voltage, the controller resets reference voltage of a low-voltage side comparator to a fourth reference voltage. According to the analog-digital converter of the present invention, it is possible to prevent device breakdown and occurrence of through current due to fluctuation of the output voltage of the integrator.