A rotational micro-electromechanical system (MEMS) having a piezo-resistor sensor is provided. The rotational MEMS device includes a pair of torsion springs that support a stage, four resistors, at least one of the resistors being formed along a center axis of the torsion springs, and electrical signal cables connected to the four resistors, wherein at least one of the torsion springs is formed in a direction on an n-type silicon substrate having a (100) plane, and the resistors formed on the at least one of the torsion springs are formed in a group direction.