Abstract: A toilet cleaning device includes an elongated and hollow guiding member, an inflatable water stopper and a pump device. The inflatable water stopper is extended from a bottom end of the guiding member and is positioned in a bottom drain of a toilet bowl. The pump device is provided at an upper end of the guiding member. The pump device is actuated to inflate the inflatable water stopper through the guiding member. Therefore, the inflatable water stopper is inflated at a predetermined size for matching with a size of the bottom drain of the toilet bowl to water-seal thereat and for raising water level in the toilet bowl when water is added.