The mini air compressor 30 also vibrates. However, a vibration damping structure 180 (FIGS. 6-7) is interposed between the bracket 66 and the platform 42 so as to isolate the base structure 40 and the tank 12 from the vibrations of the mini air compressor 30. As shown in FIG. 2, an inner edge surface 182 of the platform 42 defines an opening 183 beneath the end portion 74 of the bracket 66 beside the flywheel 32. As shown in FIGS. 6-7, a cylindrical mounting boss 190 projects downward from the bracket 66 and extends through the opening 183. The damping structure 180 engages and supports the boss 190 within the opening 183.