PURPOSE: To perform a continuous operation of a gas cleaner body using a gas cleaner even when a filter is clogged in the cleaner in which the filter for cleaning passing gas is provided in a gas passage for feeding the gas.

CONSTITUTION: A gas passage 7 has a main passage 7m for passing gas through a filter 14m, and an auxiliary passage 7b for passing the gas roundabout the filter 14m, and passage switching means 15 capable of switching between an open state for allowing passage of the gas in the passage 7b and a closed state for preventing the passage of the gas. Further, clogging detecting means S for detecting a clogged state of the filter 14m is provided, and control means C for so controlling the means 15 as to switch it to the closed state when the filter 14m is not closed and to the open state when the filter 14m is clogged based on detection information of the means S is provided.