For the surgical treatment of mitral valve disease, it is regarded that valvuloplasty is more effective surgical treatment than mitral valve replacement. After mitral valvuloplasty, surgeons have a general procedure to use a transesophageal echocardiography to assess whether the surgical treatment was performed appropriately, or not. However, the transesophageal echocardiography is one of the qualitative methods for an assessment of mitral regurgitation. If the behavior of mitral valve can be monitored from various directions, and if the mitral regurgitation can be measured quantitatively, surgeons are able to verify the effects of their surgical treatments. Therefore, the purpose of this study is to develop a sophisticated mock circulatory system, being capable of reproducing a mitral regurgitation as well as a normal hemodynamic condition, and then to evaluate the effect of valvuloplasty. Consequently, it became possible to evaluate the surgical treatment using the data obtained from the in vitro mock circulatory system, and this system can be used as a supporting tool for the cardiac surgeons.