Provided is a flash type A/D converter including a differential amplifier circuit array and a voltage comparing circuit array. The A/D converter further includes an adjusting circuit (107) for making the output dynamic range of the differential amplifier circuits coincide highly precisely with the input dynamic range of the voltage comparators, and the resistances of a plurality of voltage generating circuits (122) contained in a reference voltage generating circuit (119) belonging to the adjusting circuit (107) are connected in series. By these series connections, the area of the voltage generating circuit (122) is reduced, and the output dynamic ranges of individual differential amplifier circuits (A1 to Am+1) of the differential amplifier circuit train (102) coincide highly precisely with the input dynamic ranges of individual voltage comparing circuits (Cr1 to Crm+1) of the voltage comparing circuit array (103). Moreover, the half circuit of the voltage generating circuit (122) is used to generate a reference voltage. As a result, the area of the voltage generating circuit is made smaller.