This paper reports on the development of a robotic leg for the RoboCup Humanoid league. The leg is designed to fit the regulation of the Teen size class robot and focuses to enhance the ball kicking function, which targets meet the actual kicking ability of the early elementary school child. The design consideration and specification are discussed in relation to the previous research on human's and robot's ball-kicking performance. The first stage prototype CAD model of the robotic leg with Multimotor structure, series elastic actuator, and Gyro-cam mechanism is produced. The basic aspects of the structure and design are described.