In this study, tensile properties of a cultured osteoblast, which is one of bone cells, were measured with tensile and creep tests. As a result, the load-elongation and stress-strain diagram of the cell were obtained. In addition to the tensile test, the increase of the elongation of the cell was measured keeping the tensile load as constant in the creep test. Using these experimental results, a three-element model of the cell for viscoelasticity was derived and the value of each parameter was identified.