We propose a liquid motor using surface tension. Our liquid motor is composed of a liquid droplet, a floating plate and a lower plate. The plate floating on the droplet is rotated continuously by electrowetting actuation. The floating plate is asymmetrically and has four cogs. By electrowetting actuation, the shape of the droplet is deformed. Then, the floating plate rotates to the position where the surface energy of the sandwiched liquid takes a minimum value. On the lower plate, electrodes are patterned in an annular shape. By choosing the voltage-applied electrodes, the position of the floating plate is controlled. In this research, a 2 mm floating plate with a 500 μm silicon cube was rotated at 180 rpm. This motor is useful for optical devices because the components of the liquid motor can be made of transparent materials.