It is known that room-temperature formability of a magnesium alloy sheet is much lower than those of steel and aluminum alloy sheets. Thus, in the conventional press-forming process of a magnesium alloy sheet, a sheet and dies must be heated at above 250 °C. In the newly developed rolling process, a commercial magnesium alloy sheet is rolled at a temperature about 100 °C higher than that in the conventional rolling process. The magnesium alloy sheet processed by the new rolling process exhibits a significantly weak crystal orientation, resulting in the excellent room-temperature formability comparable to those of aluminum alloy sheets. This means that a conventional press-forming machine without heating equipment is available, and significant cost reduction and enhanced productivity are expected. In addition, since composition of the new magnesium alloy sheet is the same as those of commercial magnesium alloy sheets, conventional surface treatment processes are directly applicable.