To provide a flowing-down state observation method and a flowing- down state observation apparatus for gas that are inexpensive and can observe the flowing-down state of gas in real time.

A net-like thermosensitive color changing means 2 that generates heat due to energization and changes an outer surface color due to own temperature is formed, is provided in flowing-down air for observing the flowing-down state, is allowed to hit against flowing-down air to observe the outer surface color, and obtains the flowing-down state of gas. Additionally, instead of the thermosensitive color changing means 2, a net-like pressure-sensitive color changing means where the outer surface color is changed by pressure operating on itself is provided in the air, and is allowed to hit against flowing-down air to observe the outer surface color, thus obtaining the flowing-down state of gas.