A goal of this work is proposal and construction of Active Heart System: a simulation environment that enables anyone to see and touch heart beat in real time. In this paper, a method to express real-time graphic and haptic behaviour of a beating heart is mentioned. The data for the beating heart model was obtained from EGG-gated 3D MRI of a normal volunteer. The elastic information was assumed as a uniform value with clinically experienced elasticity. Using a real-time 3D graphics and a haptic device, a simulation environment of the beating heart was designed and implemented. After the construction, some cardiovascular surgeons evaluated the implemented system. Its visualization and beating expression were scored excellent, but some details in haptic expression were remained to be improved. Finally, for more realistic cardiovascular surgical simulation, future development of the method is discussed.