TITLE: GCN CIRCULAR NUMBER: 16487 SUBJECT: GRB140629A: Kanata/HOWPol optical observation DATE: 14/06/29 23:33:24 GMT FROM: Koji Kawabata at HASC,Hiroshima U K. Takaki, T. Nakaoka, Y. Moritani, K. S. Kawabata (Hiroshima Univ.) report on behalf of Kanata team: We performed a series of optical imaging polarimetry for the optical afterglow of GRB140629A (Yurkov et al., GCN 16478, Xin et. al GCN 16480, Bikmaev et al., GCN 16482) from 73 sec after the Swift/BAT trigger (Lien et al., GCN 16477) with HOWPol attached to the 1.5-m Kanata telescope at Higashi-Hiroshima Observatory, Japan. Calibrated with USNO-B1 catalogue, our quick-look photometry indicates that the R-band magnitude of the optical afterglow was 14.0 at the beginning of our observation, reached its peak brightness of 13.3 mag around 160 sec, and then smoothly declined. Further analysis is ongoing.