PURPOSE: To reduce the current of a current switch while keeping conversion precision, and to realize the low power consumption of a D/A converter by making a low order bit having a margin in the conversion precision into current weighting.

CONSTITUTION: A resistance value in the case an R-2R ladder circuit is seen from a switch S side is 2R/3, and the voltage Vcc-4I.2R/3 of an output terminal OUT at the time when an MSB switch S7 is closed is made to be 1/2 of a full scale, and thus, the voltage Vcc-2I.2R/3 of the output terminal OUT at the time when the next switch S6 is closed becomes 1/4 of the full scale, and the voltage of the output terminal OUT at the time when the switch S5, S4... of an R-2R ladder resistance part is closed becomes 1/8, 1/16... of the full scale. The current weighting reduces a wasteful current, and ineffective power consumption is reduced.