The utility model relates to a continuous coasting crystallizer sphenoidal spring piece which is composed of a pressure sensor, a displaying instrument which is connected with the pressure sensor, a sphenoidal spring bag, an oil cylinder and a percent meter, and the utility model also relates to a pressure sensor detecting device. The utility model is characterized in that the pressure sensor (1) and the displaying instrument are fixed at one side in a groove bracket (6). A jacking block (7), a spring bag (3) and a hydraulic pressure jack (8) are orderly arranged in the same axial direction with the pressure sensor (1). The hydraulic pressure jack (8) is fixed at the other side in the groove bracket (6). The lower end of the sphenoidal spring bag (3) is provided with a pulley (9), and the pulley (9) is contacted with the bottom plate face of the groove bracket (6). The oil cylinder (4) is arranged at the adjacent part of the sphenoidal spring bag (3) and the jacking block (7). The status of the continuous coasting crystallizer sphenoidal spring bag and the pressure sensor can be detected accurately by the device of the utility model, and successful process of production can be well guaranteed.