A fluorescence observing apparatus has an illumination system for irradiating a specimen with exciting light and an observation system for observing fluorescent light emanating from the specimen. The pressure sensor measures the air pressure of a tire. An open top portion is defined by the front, back, left, and right panels at an end of the bag opposite the closed bottom panel. In this way, inadvertent activating of test functions on the chip is effectively prevented by simple measures, for instance by inserting only one additional fabrication step.