Ultra-luminous IR galaxies (ULIRGs) are thought to represent rapidly growing phase of massive galaxies before quenching of their star formation through AGN feedback. One ULIRG AKARI J0916+0730 identified in our Subaru/FOCAS follow-up observation, indicates signatures of extremely strong ionized outflow in its optical emission line profiles. The [OIII] line shows FWHM of 1700 km/s and blue shifts of 816 km/s in relative to the stellar absorption lines. Furthermore low-ionization [OII] doublets also show large FWHM of 1088 km/s, which indicates the outflow can extend beyond the nuclear / bulge region. The co-existence of strong outflow and vigorous starburst (1000 Msun/yr) suggests that the object is possibly in the intermediate stage of evolution in which the feedback just becomes effective and begins to sweep out the ISM in the entire galaxy.