A shower tube cleaning device for a filter for a water tank in which clean water from the filter is returned to the interior of the water tank through the shower tube, which is provided with a plurality of nozzles, wherein an operating rod (11) passing through the interior of the shower tube (5) is linked to a cleaner (10) slidably provided within the shower tube (5), a knob (12) is fixed to the free end of the operating rod (11), and pushing and pulling the knob (12) makes the cleaner (10) reciprocatingly slide to thus scrape off foreign matter within the shower tube (5). This enables an inner face of the shower tube to be cleaned while the shower tube is linked to the filter.