The author succeeds in manufacturing a portable high speed Brown-tube oscillograph which can be used to take a photograph of the high speed phenomena such as in 10⁻⁷ seconds, as well as the relatively slow phenomena in 10⁻² seconds.
After many fundamental and practibal experiments, this portable set is proved to be fitted for practical problems. In this paper, the author describes 1. general idea of the set, 2. the connection diagram of the electric circuits, 3. the eautions of manufacturing, 4. the experimental results. In the experimental results, the methods of synchronising between the phenomena under research and the oscillograph are written. The grid control methods of starting the time axis of the oscillograph are also written. In conclusion, the author believes that the fields of application of this set are enlarging.