The utility model discloses a check-type and mechanical sensor device for an air preheater. The device comprises a probe and proberod component, a sensor mounting bracket component, a corrugated tube component and a sensor bottom plate component, wherein the head end of the probe and proberod component is hinged with the sensor mounting bracket component, and the tail end of that is arranged in the sensor bottom plate component; the sensor mounting bracket component is welded onto a fan-shaped plate of the air preheater; the corrugated tube component is fixedly mounted on the sensor bottom plate component; an adjustable probe is arranged at the head end of the probe and proberod component via a probe hole seat; and a check element is arranged on the sensor bottom plate component. In the device provided by the utility model, the components can be independently mounted; the safe, reliable and mechanical sensor is adopted and mounted in an air leakage control system of the air preheater; and a separation blade adjustment technology is adopted for adjusting the sensor outside the air preheater, so that the device has wide application range in the air leakage control system.