PURPOSE: To enable the burying of an instrument containing a seismometer and the like by correcting the bearing of a tube having a key with a bearing measuring device and an instrument body with a notch moving into the key after the tube is sent into a deep well.

CONSTITUTION: A tube 2 connected to a part of a short dielectric tube 2b having a key 3 at the lower end of a part 2a of a long steel pipe is sent into a deep well 1. The key 3 drops into a notch 7 through cam faces 8a and 8b while a first instrument body 5 containing a bearing measuring device 4 is hanged by a rope 6. At this point, the instrument body 1 is pulled out above the ground to observe the reading of the bearing measuring device 4. According to the reading, the tube 2 is rotated properly to turn the key 3 so that the instrument body 1 is sent into the tube 2 again to measure the bearing of the key 3. This operation is repeated until the key 3 attains the specified bearing. Thereafter, while a second instrument body 10 containing an instrument 9 such as a seismometer hangs with a cable 11 for drawing signals, the key 3 moves into a notch 12 through cam faces 13a and 13b and is set at the specified bearing of the instrument 9. Then, it is fixed with the injection of a cement.