An infusion beverage brewing device includes a filter assembly and a brewing mechanism. The filter assembly has an outer filter cup and an inner filter cup. The inner filter cup has an inner cup-body, and the outer filter cup has an outer cup-body. A gap and a vapor diffusion outlet are formed between the outer cup-body and the inner cup-body. The outer filter cup has a bottom outlet disposed a sealing device. The brewing mechanism has a cup retainer, a cover and a controlling device. The cover is disposed on the cup retainer, and the controlling device is connected to the cover. The filter assembly is disposed in the cup retainer. The cover is selectively disposed on the filter assembly. The cover is disposed with a sprinkle-nozzle and a vapor portal. The vapor portal corresponds to the vapor inlet of the inner filter cup.