An integrator circuit device for integrating an input signal includes an integrator configured to perform integration on an input signal in a positive direction or a negative direction to generate an output voltage, and a switching controller configured to control a switch so that the integrator performs the integration on the input signal in the positive direction or the negative direction. The integrator circuit device further includes a counter configured to count a number of times an integration direction of the integrator is changed, and a controller configured to determine a final output voltage, based on the counted number of times the integration direction is changed and the output voltage.