A reflex enclosure, includes an enclosure body, a loudspeaker, a waveguide portion and a vibration unit; a rearward sound wave generated from the loudspeaker is guided 360 degree (in all directions) from the outside of the waveguide portion to the inside of the waveguide portion, and then push the vibration unit to generate vibration to generate a corresponding sound wave, thereby reducing a standing wave ratio of the rearward sound wave in a sound room to obtain a better timbre. Furthermore, the length of a rearward sound wave guiding distance can be extended, allowing the sound wave to have the effect of extending toward a low frequency compass. In addition, the rearward sound wave is allowed to compress to increase a vibration unit pushing force, thereby obtaining a better sound effect.