The present invention relates to a neutral particle beam processing apparatus. More specifically, the present invention relates to a neutral particle beam processing apparatus comprising a plasma discharging space inside which processing gases are converted to plasma ions through a plasma discharge, a heavy metal plate which converts the plasma ions into neutral particles through collisions, a plasma limiter which prevents plasma ions and electrons from passing through and allows the neutral particles produced by collisions of the plasma ions with the heavy metal plate to pass through, and a treating housing inside which a substrate to be treated is located, wherein the plasma discharging space is sandwiched between the heavy metal plate and the plasma limiter.