Film formation method

A film formation method comprising:

• arranging a non-conductive long thin tube in a chamber capable of adjusting internal pressure:
• generating plasma inside the long thin tube while a source gas containing hydrocarbon is supplied into the chamber;
• and
• forming a diamond-like carbon film on an inner wall surface of the long thin tube,
• the long thin tube being disposed in the chamber such that a discharge electrode is disposed at one end of the long thin tube and such that the other end of the long thin tube is opened, and
• an alternating current bias being intermittently applied between the discharge electrode and a counter electrode spaced apart from the long thin tube.

A film formation apparatus comprising:

• a chamber capable of adjusting an internal pressure;
• a gas feeder configured to feed a hydrocarbon gas into the chamber;
• a discharge electrode and a counter electrode provided in the chamber;
• and
• a power supply configured to intermittently apply an AC voltage between the discharge electrode and the counter electrode,
• the discharge electrode being attached to one end of a non-conductive long thin tube to discharge electricity with the counter electrode spaced apart from the long thin tube, and
• plasma being thus generated in the long thin tube to form a diamond-like carbon film on an inner wall surface of the long thin tube.