A clothes treatment apparatus comprising: a case defining therein a treatment chamber for accommodating clothes; a steam unit for supplying steam to the treatment chamber, wherein the steam unit comprises a heater for heating water; a blower unit for drawing air from the treatment chamber; an inlet temperature sensor for measuring an inlet temperature, which is a temperature of air drawn from the treatment chamber by the blower unit; a heat pump unit for heating air drawn by the blower unit to supply the heated air into the treatment chamber; and a control unit for controlling the steam unit, the blower unit and the heat pump unit, wherein the control unit is configured to: perform a preheating cycle by supplying power to the heater for preheating the heater and operating the blower unit for drawing the air from the treatment chamber without operating a heat pump unit, wherein the inlet temperature sensor measures a preheated inlet temperature T1, which is a temperature of air drawn by the blower unit, when starting operation of the blocker unit, perform a steam cycle by operating the steam unit for supplying steam to the treatment chamber after completion of the preheating of the heater, perform a cooling cycle by operating the blower unit for lowering a temperature inside the treatment chamber after halting operation of the steam unit, and perform a drying cycle, after the cooling cycle, by controlling the heat pump unit based on the preheated inlet temperature T1 for heating air and operating the blower unit for discharging the heated air into the treatment chamber. a case defining therein a treatment chamber for accommodating clothes; a steam unit for supplying steam to the treatment chamber, wherein the steam unit comprises a heater for heating water; a blower unit for drawing air from the treatment chamber; an inlet temperature sensor for measuring an inlet temperature, which is a temperature of air drawn from the treatment chamber by the blower unit; a heat pump unit for heating air drawn by the blower unit to supply the heated air into the treatment chamber; and a control unit for controlling the steam unit, the blower unit and the heat pump unit, wherein the control unit is configured to: perform a preheating cycle by supplying power to the heater for preheating the heater and operating the blower unit for drawing the air from the treatment chamber without operating a heat pump unit, wherein the inlet temperature sensor measures a preheated inlet temperature T1, which is a temperature of air drawn by the blower unit, when starting operation of the blocker unit, perform a steam cycle by operating the steam unit for supplying steam to the treatment chamber after completion of the preheating of the heater, perform a cooling cycle by operating the blower unit for lowering a temperature inside the treatment chamber after halting operation of the steam unit, and perform a drying cycle, after the cooling cycle, by controlling the heat pump unit based on the preheated inlet temperature T1 for heating air and operating the blower unit for discharging the heated air into the treatment chamber. perform a preheating cycle by supplying power to the heater for preheating the heater and operating the blower unit for drawing the air from the treatment chamber without operating a heat pump unit, wherein the inlet temperature sensor measures a preheated inlet temperature T1, which is a temperature of air drawn by the blower unit, when starting operation of the blocker unit, perform a steam cycle by operating the steam unit for supplying steam to the treatment chamber after completion of the preheating of the heater, perform a cooling cycle by operating the blower unit for lowering a temperature inside the treatment chamber after halting operation of the steam unit, and perform a drying cycle, after the cooling cycle, by controlling the heat pump unit based on the preheated inlet temperature T1 for heating air and operating the blower unit for discharging the heated air into the treatment chamber.