An interdigital capacitor and a multiplying digital-to-analog conversion circuit are provided. The interdigital capacitor includes at least one first metal layer. The following components are disposed in each first metal layer: a first electrode; at least one first finger metal connected to the first electrode; a second electrode; and a plurality of second finger metals connected to the second electrode, and at least one third finger metal connected to the second electrode. The at least one first finger metal is alternately disposed with the plurality of second finger metals to form capacitors, and the at least one third finger metal is a dummy (dummy) finger metal.