This paper describes the implementation and the evaluation of the five-key mouse with built-in dialog control. The mouse is interfaced to a Symbolics-3600 list machine, using RS-232C, and the implementation of the universal commands is tried on ZMACS editor. Through both results of experiment and the key-stroke level model, the operation time of the five-key mouse is shorter than the three-key mouse. and the effect of the five-key mouse is confirmed.