A speaker unit for a projector includes a first speaker, a fixing portion and a second speaker. Either the first speaker or the second speaker has a central hole to hold the vertical post of a projector. Two holes that are diagonally opposing each other are provided in the inner wall of the central hole. The two holes of the fixing portion may align with the two holes of the first speaker and fasteners may be used to fixedly connect the first speaker with the vertical post. A connective portion is provided on either of the two vertical walls of the first speaker and a connective portion is provided on either of the two vertical walls of the second speaker. Therefore, the second speaker may be connected with the first speaker by these connective portions.