A flash A/D converter includes a plurality of master comparators for comparing a plurality of reference voltages and an input analog signal to absorb a current with a constant value from a non-inverted output or inverted output of each master comparator, a plurality of constant current sources, a plurality of load resistors and a plurality of slave comparators for outputting desired digital signals. The constant current value of one of the constant current sources coupled to a signal line coupled to the input of the slave comparator of a lower bit side is set to a value larger than that of one of the constant current sources coupled to a signal line coupled to the input of the slave comparator of a higher bit side. Thereby, it is possible to provide a flash A/D converter which has a low power consumption and a high speed.
