A torque sensor comprising: a first structure to be coupled to an object to be measured; a second structure; a plurality of third structures (13a, 13b, 13c, and 13d) coupling the first structure and second structure to each other; a first bridge circuit including a plurality of first strain sensors (G1-G4) configured to detect force to be transmitted between the first structure and the second structure; a second bridge circuit including a plurality of second strain sensors (G5-G8) configured to detect force to be transmitted between the first structure and the second structure; a first detecting circuit configured to detect a first output voltage of the first bridge circuit; a second detecting circuit configured to detect a second output voltage of the second bridge circuit; a memory configured to store the first output voltage from the first detecting circuit and the second output voltage from the second detecting circuit; and a controller configured to output a signal indicating an abnormality when a difference between the first output voltage of the first bridge circuit and the second output voltage of the second bridge circuit is greater than a first threshold voltage; characterized in that each of the strain sensors (G1-G8) is constituted of a thin-film resistive element provided on a metallic plate through an insulating film, and the metallic plate of each of the strain sensors (G1-G8) is fixed to the surface of the third structure (13a or 13c) by means of screwing, and in that the controller is configured to stop the first bridge circuit when a difference between the first output voltage supplied from the first detecting circuit and the first output voltage stored in the memory is greater than a second threshold voltage, and to stop the second bridge circuit when a difference between the second output voltage supplied from the second detecting circuit and the second output voltage stored in the memory is greater than the second threshold voltage. a first structure to be coupled to an object to be measured; a second structure; a plurality of third structures (13a, 13b, 13c, and 13d) coupling the first structure and second structure to each other; a first bridge circuit including a plurality of first strain sensors (G1-G4) configured to detect force to be transmitted between the first structure and the second structure; a second bridge circuit including a plurality of second strain sensors (G5-G8) configured to detect force to be transmitted between the first structure and the second structure; a first detecting circuit configured to detect a first output voltage of the first bridge circuit; a second detecting circuit configured to detect a second output voltage of the second bridge circuit; a memory configured to store the first output voltage from the first detecting circuit and the second output voltage from the second detecting circuit; and a controller configured to output a signal indicating an abnormality when a difference between the first output voltage of the first bridge circuit and the second output voltage of the second bridge circuit is greater than a first threshold voltage; characterized in that each of the strain sensors (G1-G8) is constituted of a thin-film resistive element provided on a metallic plate through an insulating film, and the metallic plate of each of the strain sensors (G1-G8) is fixed to the surface of the third structure (13a or 13c) by means of screwing, and in that the controller is configured to stop the first bridge circuit when a difference between the first output voltage supplied from the first detecting circuit and the first output voltage stored in the memory is greater than a second threshold voltage, and to stop the second bridge circuit when a difference between the second output voltage supplied from the second detecting circuit and the second output voltage stored in the memory is greater than the second threshold voltage.