Time optimal control method for quadruped walking robots has been developed and installed into a practical robot system. Support legs are modeled as five-link manipulators and swinging legs are modeled as a two link manipulator whose time optimal control theory has already been established by Bobrow. However, the path of swing legs was designed as a horizontal line for simplicity, so the tips of the swing legs were dragged and robot could not walk at theoretical velocity. A new trajectory of the leg tips is designed to avoid the dragging.