Highly integrated infused box made of composite material with two skins (3), several ribs (4), several stringers (5), a front spar and a rear spar, comprising a first semibox (1) and a second semibox (2) joined by connecting means, in which the first semibox (1) comprises one skin (3) and the ribs (4), and the second semibox (2) comprises one skin (3), the front spar, the rear spar and the stringers (5). A manufacturing method is also provided, which comprises forming processes for the first semibox (1), the second semibox (2) and an assembly process of the first semibox (1) with the second semibox (2).