It is really interesting to know how a blood flow has an influence on a touch sensitivity during human fingertip exploration over an environment. In this paper, we examine experimentally how the touch sensitivity is changed under the condition that the blood flow is interrupted compulsorily by pressing the proximal phalange of human finger. Through the weight discrimination test based on Weber's Law, we found that the touch sensitivity improves temporarily with the statistical significance test of below 0.1 %, when a finger proximal phalange is bound and pressed. Experimental results also show that there exists a meaningful correlationship between the stiffness of fingertip and the touch sensitivity.