To improve the movement ability of humanoid robots, instead of traditional methods dependent on only power of actuators, there is possibility that utilizing elasticity inspired from collaboration of muscle and tendon of human is effective to achieve high-power movement. In this study, we aimed to realize a jumping motion that accumulates energy more appropriately in spring by combining active joint driving with spring behavior like human tendons and muscles. We proposed a countermovement jump method using the resonance with the leg's active pushing-off movement and leg stiffness. To achieve active pushing-off and joint stiffness, we developed a new joint mechanism using leaf springs and an actuator unit with a worm gear. We then performed experiments to evaluate the effectiveness of the proposed mechanism and methods. Finally, the robot achieved a countermovement jump using active kicking and leg's elasticity.