Abstract: A speaker apparatus includes a cabinet divided by a partition plate into a front compartment and a rear compartment, a speaker unit mounted on the partition plate so that the sound radiating direction is towards said front compartment, an internal passive radiator mounted on the partition plate, and a duct formed on an outer wall section of the front compartment for extending in the same direction as the sound radiating direction of the speaker unit. The speaker unit and the internal passive radiator mounted on the partition plate dividing the cabinet into a front compartment and a rear compartment render the rear compartment into a hermetically sealed box and constitute a resonance circuit. The sound is radiated via a duct formed on the outer wall section of the front compartment.