To easily analyze the causes of anomalies in a specimen in a navigation system.

A navigation system specimen 5 is mounted to the vibrating base 4a of a vibration testing machine 4, and a predetermined load is exerted on the specimen 5 by a temperature humidity cycle testing machine 3 and the vibration testing machine 4 under the control of a central control computer 1. The specimen 5 in this state and a non-specimen 6 are activated, and the images of the displays of the specimen 5 and the non-specimen 6 are picked up by CCD cameras 21 and 22. Both picked-up images are compared with each other to determine anomalies, and the image of the display screen of the specimen 5 at the time when the anomalies occur and test load conditions (temperature, humidity, wind velocity, vibration, etc.), at the time are stored in a storage device 23 when the anomalies occur.