A separable air purifying apparatus is provided, in which a number of purifiers whose purifying capabilities for particular pollutants are reinforced by each purifier are disposed in a space meeting each purifying characteristic in order to enable an independent operation for a custom-made purification, and are integrally combined with each other to thereby make a combination of a driving ratio of each purifier according to a degree of pollution and perform a combination operation of purification. The separable air purifying apparatus inhales external air by ventilation modules incorporated in respective cases and purifies the external air by filter members, to then discharge out the purified air. That is, the separable air purifying apparatus includes controllers controlling the ventilation modules and a main purifier and an auxiliary purifier each which are independently operated by respective power supplies. Here, an output terminal is formed in the main purifier and an input terminal is formed in the auxiliary purifier. When assembling the main and auxiliary purifiers, the input terminal of the auxiliary purifier is connected with the output terminal of the main purifier, to thus enable the controller of the main purifier to drive the ventilation module of the auxiliary purifier, and to accordingly enable a combination operation of the main and auxiliary purifiers.