An air-conditioning system comprising: a first air-processing apparatus having a first inlet, formed in one surface thereof perpendicular to a floor or a ceiling, and a first outlet, formed in another surface thereof perpendicular to the first inlet, the first air-processing apparatus being configured to induce air introduced into the first inlet to exchange heat with refrigerant and to be delivered to the first outlet: and wherein the first air-processing apparatus comprises a first pre-filter disposed in the first inlet, characterised in that the air conditioning system further comprising: a second air-processing apparatus having a second outlet, formed therein so as to be open in a same direction as the first outlet, and a second inlet, formed therein so as to be open in a same direction as the first inlet, wherein the air-conditioning system is configured to be driven in a combined operation mode in which the first air-processing apparatus and the second air-processing apparatus are configured to operate simultaneously, or is configured to be driven in an independent operation mode in which one of the first air-processing apparatus and the second air-processing apparatus is configured to operate, wherein the first air-processing apparatus and the second air-processing apparatus are different types of air-processing modules which are combined with each other so as to extend in a longitudinal direction, wherein the second air-processing apparatus comprises a second pre-filter disposed in the second inlet, and wherein the first air-processing apparatus and the second air-processing apparatus are disposed adjacent to each other, wherein the air-conditioning system further comprises: a guide rail disposed on one side of the first air-processing apparatus and one side of the second air-processing apparatus; and a filter cleaner configured to automatically move along the guide rail when operation is stopped in order to clean at least one of the first pre-filter or the second pre-filter. a second air-processing apparatus having a second outlet, formed therein so as to be open in a same direction as the first outlet, and a second inlet, formed therein so as to be open in a same direction as the first inlet, wherein the air-conditioning system is configured to be driven in a combined operation mode in which the first air-processing apparatus and the second air-processing apparatus are configured to operate simultaneously, or is configured to be driven in an independent operation mode in which one of the first air-processing apparatus and the second air-processing apparatus is configured to operate, wherein the first air-processing apparatus and the second air-processing apparatus are different types of air-processing modules which are combined with each other so as to extend in a longitudinal direction, wherein the second air-processing apparatus comprises a second pre-filter disposed in the second inlet, and wherein the first air-processing apparatus and the second air-processing apparatus are disposed adjacent to each other, wherein the air-conditioning system further comprises: a guide rail disposed on one side of the first air-processing apparatus and one side of the second air-processing apparatus; and a filter cleaner configured to automatically move along the guide rail when operation is stopped in order to clean at least one of the first pre-filter or the second pre-filter. a guide rail disposed on one side of the first air-processing apparatus and one side of the second air-processing apparatus; and a filter cleaner configured to automatically move along the guide rail when operation is stopped in order to clean at least one of the first pre-filter or the second pre-filter.