Abstract: The present invention relates to a sealed box apparatus for a pool cleaning machine wherein the sealed box is installed inside the body of the pool cleaning machine. The box contains and seals electronic devices for the cleaning machine. At least one waterproofed tube is provided for inputting and outputting wires for connecting the electronic devices sealed inside the box with peripherals. A transparent portion is installed on one side of the box. A humidity display is installed inside the box, and corresponds to the position of the transparent portion. The sealed box provides an excellent airproof seal for protecting the inside electronic circuits from being waterlogged, and to provide excellent heat elimination, while leakage into the sealed box may be conveniently monitored in real-time.