The present application relates to a selective distillation apparatus and a distillation method, the apparatus allowing a control unit to change the operation states of a reflux device, a reboiler, asupply line, a discharge line, and a connection line into an activated or deactivated state according to the types of materials used for distillation, such that two distillation columns can both be switched into a serial connection mode and a parallel connection mode, thereby enabling the selective operation of a high-efficiency operation and a high-capacity operation of the distillation apparatus.