In this paper, the circular-arc curvilinear tooth gear drive is proposed. The gear and pinion tooth surfaces are generated by two complemented circular-arc rack cutters with curvilinear tooth-traces. According to the theory of gearing, the mathematical model of the proposed gear is developed. The tooth contact analysis technique is utilized to investigate the kinematical errors of circular-arc curvilinear tooth gear drives under different assembly errors. Contact patterns of the circular-arc curvilinear tooth gear drive are simulated by the developed computer-aided tooth contact analysis programs and surface topology method. Numerical examples are presented to show the kinematical errors of the circular-arc curvilinear tooth gear set under different assembly conditions. Relations among the circular-arc tooth profile, curvilinear tooth-trace, contact ratio, contact pattern, and kinematical error are also demonstrated by numerical examples.