A DA converter circuit is provided for use in a .DELTA..SIGMA. AD modulator. The DA converter circuit includes a DA converter of segment switched capacitor type. The DA converter includes an operational amplifier, capacitors as connected in parallel to each other to supply electric charges to the operational amplifier, an electrically charging switch for switching of electrically charging electric charges onto the respective capacitors or not, and an electrically discharging switch for switching or not electrically discharging electric charges from the respective capacitors or not. A switch device performs either one of the electrically charging, the electrically discharging, grounding, and polarity inversion onto the respective capacitors. A controller controls the electrically charging switch, the electrically discharging switch and the switch device to execute a process of second-order DWA algorithm for performing a second-order noise shaping of a non-linearity of the DA converter circuit.