Tensile tests with loading and unloading under various strain rates ε were performed for TiNi shape memory alloy wires at various constant temperatures. The influence of strain rate on the stress-strain-temperature relationship was investigated. The main results were summarized as follows. (1) For ε<10%/min, the martensitic transformation stress and its reverse transformation stress did not depend on ε. These stresses were almost constant in the transformation regions. (2) For ε≥10%/min, the martensitic transformation stress increased and its reverse transformation stress decreased with an increase in ε. These stresses fluctuated in the transformation regions. (3) The influence of ε on the transformation stress due to R-phase transformation was slight. (4) The recoverable strain energy density depended slightly on ε but increased significantly in proportion to temperature. The dissipated strain energy density depended slightly on temperature but increased in proportion to ε for ε≥1%/min. (5) The influence of ε on deformation properties is important for evaluation of mechanical properties of shape memory alloy elements.