This study developed a haptic sensation system of the stiffness of an object using muscle contraction induced by EMS. To generate a haptic sensation corresponding to the force applied on the hand, we measured the force generated at the hand when electric stimulation was applied to a particular muscle. Once we had obtained a model of the relationship between the applied electric stimulation and the generated force, we determined the intensity of the electric stimulation required to simulate the target stiffness. We analyzed the performance of our system by measuring the perceived stiffness in human experiments. The experimental results show a positive correlation between the target stiffness and perceived stiffness.