An A/D converter has a series of M delay units through which a pulse signal is transmitted while being delayed in each delay unit by a delay time depending on a level of an analog signal. A unit of the converter latches the pulse signal outputted from each delay unit at N sampling times to hold M×N latched data. Another unit of the converter receives the M×N pieces of latched data as a piece of combined data composed of the latched data arranged in an order corresponding to an arranging order of M×N sampling points in the pulse signal, converts the combined data into numeral data, corresponding to a position of the pulse signal in the delay units, at one time, and produces converted digital data corresponding to the level of the analog signal from the numeral data.