A steam/ironing dual mode cleaning apparatus includes a housing defining a receiving chamber, a water tank unit mounted in the receiving chamber and adapted to hold water, a steam boiler mounted in the receiving chamber and adapted to boil water into steam, and a water pump unit mounted in the receiving chamber and horizontally aligned with the water tank unit and the steam boiler, the water pump unit having a water inlet fitting connected to a water output port of the water tank unit through a first water pipe, a water outlet fitting connected to a water input port of the steam boiler through a second water pipe, and a motor pump controlled to pump water from the water tank unit to the steam boiler for boiling.