Abstract: Various digit display units and digit shift means disposed between adjacent digit display units are mounted on two parallel supporting shafts extending between opposing side walls of a frame. A motor for driving the least significant digit is mounted on the outside of one side wall, and a time switch mechanism comprising a timer setting wheel, a cam gear and a timer lever is disposed between the other side wall and a sub-plate spaced therefrom. Cams are secured on the opposite ends of a shaft which supports the digit shift means, one of the cams engaging the timer lever, while the other cam engaging a buzzer operating member vibrated by the leakage flux of the motor. The operation of the timer lever is transmitted to the buzzer operating member through the digit shift means supporting shaft.