A clothes treatment apparatus comprising: a cabinet partitioned into a treatment chamber for allowing clothes to be hung therein, a cycle chamber for allowing machinery to be installed therein, and a tank installation space configured to allow a removable tank to be installed therein; a door for opening and closing the cabinet; a steam unit disposed in the cycle chamber for supplying steam into the treatment chamber; a heat pump unit disposed in the cycle chamber for circulating air in the treatment chamber and conditioning the air that is circulated; a water supply tank disposed in the tank installation space, such that the water supply tank is separably installed in the tank installation space and is connected to the steam unit, configured to supply water to the steam unit; a drainage tank disposed in the tank installation space, such that the drainage tank is separably installed in the tank installation space, configured to store condensed water generated in at least one selected from between the treatment chamber and the heat pump unit; a water supply level sensor disposed in the water supply tank configured to directly sense a level of water stored in the water supply tank; a drainage level sensor disposed in the drainage tank configured to directly sense a level of water stored in the drainage tank; a partition plate for partitioning an interior of the cabinet into upper and lower interior parts such that the treatment chamber and the cycle chamber are partitioned from each other; and a tank module frame for partitioning the interior of the cabinet below the partition plate into front and rear interior parts such that the cycle chamber and the tank installation space are partitioned from each other; wherein the water supply level sensor comprises: a float case fixed in the water supply tank; a float installed in the float case such that the float is movable upward and downward in the float case by buoyancy; and a sensor installed at the cabinet and configured for sensing a magnetic force of the float. a cabinet partitioned into a treatment chamber for allowing clothes to be hung therein, a cycle chamber for allowing machinery to be installed therein, and a tank installation space configured to allow a removable tank to be installed therein; a door for opening and closing the cabinet; a steam unit disposed in the cycle chamber for supplying steam into the treatment chamber; a heat pump unit disposed in the cycle chamber for circulating air in the treatment chamber and conditioning the air that is circulated; a water supply tank disposed in the tank installation space, such that the water supply tank is separably installed in the tank installation space and is connected to the steam unit, configured to supply water to the steam unit; a drainage tank disposed in the tank installation space, such that the drainage tank is separably installed in the tank installation space, configured to store condensed water generated in at least one selected from between the treatment chamber and the heat pump unit; a water supply level sensor disposed in the water supply tank configured to directly sense a level of water stored in the water supply tank; a drainage level sensor disposed in the drainage tank configured to directly sense a level of water stored in the drainage tank; a partition plate for partitioning an interior of the cabinet into upper and lower interior parts such that the treatment chamber and the cycle chamber are partitioned from each other; and a tank module frame for partitioning the interior of the cabinet below the partition plate into front and rear interior parts such that the cycle chamber and the tank installation space are partitioned from each other; wherein the water supply level sensor comprises: a float case fixed in the water supply tank; a float installed in the float case such that the float is movable upward and downward in the float case by buoyancy; and a sensor installed at the cabinet and configured for sensing a magnetic force of the float. a float case fixed in the water supply tank; a float installed in the float case such that the float is movable upward and downward in the float case by buoyancy; and a sensor installed at the cabinet and configured for sensing a magnetic force of the float.