The invention discloses an assembled head-mounted module for sensing brain activity and a head-mounted device for sensing brain activity. The assembled head-mounted module is adapted to be worn on a head of a living body and includes bases and connecting strips. Each base has a hollow portion for accommodating a signal extractor that is configured to extract brain activity signals. The connecting strips are detachably joined to the bases. The bases respectively correspond to portions of the head of the living body suitable for extracting brain activity signals when the assembled head-mounted module is worn on the head of the living body. In the invention, the structure can be flexibly assembled according to practical usage and the components can be joined or disjoined freely, thereby having more flexibility for practical applications.
