The analytical instruments in the laboratory are stable isotope ratio mass spectrometer, Orbitrap, tandem mass spectrometer, and other mass spectrometers. Most of these instruments are demonstrators or used equipment, and were purchased by research funds. All of these analyzers are very expensive (tens of millions of yen or more), and the maintenance cost is also very high compared to the price of the equipment. We have learned various techniques from the manufacturer's engineers, and are now able to repair most of them by ourselves. We have also cut costs by importing many of the parts from overseas. One of our goals is to conduct inexpensive and interesting research, and we are engaged in a daily trial and error process with our students.