To exactly and instantaneously judge change of an object without directly performing mounting operation to the object whose collapse is concerned.

The change of image data in back and forth from a digital camera device 1 is monitored and the collapse of the object A is predicted by a monitoring and control means 25. Since electric signals are successively outputted from the digital camera device 1, prediction of the collapse of the object A is promptly judged if the change of the image data is monitored by the monitoring and control means 25. In addition, since the change of the object A is directly and visually grasped, the prediction of the collapse is exactly judged in comparison with the conventional device to observe change of temperature of the object A.