[Problem] The clinical condition of a patient cannot be improved. [Solution] A local-cleaning type air purifier 1 equipped with: a casing 2 having an air suction port 2a and an air discharge port 2b； a fan 3 arranged in the interior of the casing 2； a filter 4 through which air currents generated by the fan 3 pass； a hydrogen generation device 5 that generates hydrogen gas in the interior of the casing 2； and a tank 7 storing water supplied to the hydrogen generation device 5. Air in which the hydrogen gas has been mixed is discharged from the air discharge port 2b.
