A stress sensor in which the direction and magnitude of a stress being applied to a post bonded to or integrated with an insulating board can be grasped from variation in the resistance of resistor elements being stimulated by application of the stress while suppressing variation in the shape of each resistor. The resistor element comprises a resistor formed, by screen print, between a pair of electrodes for the resistor element, i.e. circuit pattern electrodes, arranged on the surface of the insulating board. The electrode is connected, through a conductor, with a board terminal part arranged at one end of the insulating board. The electrode and the conductor or a print accuracy adjusting member have a constant height from the surface of the insulating board. Arrangement of the conductor, electrode and print accuracy adjusting member is entirely identical or similar for the resistor elements in the vicinity thereof.