An infant chair apparatus includes a support frame, a seat pivotally connected with the support frame about a pivot axis and provided with a coupling member, and a swing drive assembly connected with the seat and the support frame. The swing drive assembly includes a spring having a first end affixed with the support frame and a movable second end, wherein the spring is operable to apply a spring force that is converted into a driving torque applied on the coupling member to impart a swing motion to the seat, and a torque adjusting mechanism respectively connected with the second end of the spring and the coupling member, the torque adjusting mechanism being operable to adjust a position of the coupling member relative to the seat.