The bendability and deformation behavior of a magnesium alloy tube during press bending is experimentally investigated to clarify the effect of forming temperature. Bending experiments using a mandrel of wires are carried out at room temperature and at 473K. A magnesium alloy AZ31 circular tube with a 25.4mm outer diameter and a 1.5mm wall thickness is used in the experiments. The unique deformation behavior of the AZ31 tube is discussed in detail. In the bending experiments, the AZ31 tube was able to be bent with the internal mandrel at an R₀/D₀ of 2 and 473K. The bending limit of the AZ31 tube is considered to be enhanced, for the tube having a low average flow stress and a low r-value at room temperature, and a high average flow stress and a relatively low r-value at an elevated temperature in the compression range.