To provide a speaker mounting device that can be installed by simplifying the electrical wiring work between an amplifier and a speaker by facilitating the mounting work of the speaker in a compartment, and by moving and adjusting the speaker to an appropriate position for maximizing acoustic effect.

A guide rail member 2 incorporating four electrode wires is laid on a ceiling surface 12 or a wall in the compartment 11, and the speaker 5 which has four contact electrodes that slidably contact each electrode wire of the guide rail member 2 is removably and slidably fitted to an optional position of the guide rail member 2.