A body fluid sampling device comprises an elastic membrane arranged at a part of a hermetically sealed housing having a communication path with a check valve and a needling means arranged beneath the membrane. As the membrane is pressed by a fingertip, the needling means needles through the membrane and further the skin of the fingertip to exude blood. As the fingertip is then separated from the membrane, the exuded blood is efficiently introduced into the housing due to the negative pressure produced in the internal region by the elastic movement of the membrane.
