The dynamic behavior of a bubbling fluidized bed that requires only vibration and not the use of an external air supply system as a driving source was analyzed in detail. Alumina particles of 8 mu m in diameter were placed into a cylindrical glass tube with a bottom plate, and a small horizontal vibration of 300 Hz was applied using a piezoelectric vibrator. The bubbles generated in the powder bed and the particle behavior were then observed using a high-speed camera. In addition, the pressure distributions in the powder bed and pressure-time variations were measured. The time series of images showed that bubbles were continuously generated at the bottom sidewall of the glass tube and rose vertically in series in the powder bed; and the powder layers between bubbles often collapsed, with repeated coalescence of bubbles. The bubble movement generated not only upward flow but also downward flow, resulting in formation of circulation flows in the powder bed. Pressure measurements showed that the bubbles flowing upward had a positive pressure, and those flowing downward had a negative pressure; and the pressure in the bubbles oscillated with the same frequency as the external vibration. Further, through experiments where the bottom plate was separated from the bottom edge of the glass tube with a small gap and both the plate and tube were vibrated, it was shown that bubbles were generated by the effect of compression in the powder bed. Air would then enter through the small gap owing to the negative pressure arising from the convection flow, forming a vigorous bubbling fluidized bed.