Conversion of pure spin current to charge current in single-layer graphene (SLG) is investigated by using spin pumping. Large-area SLG grown by chemical vapor deposition is used for the conversion. Efficient spin accumulation in SLG by spin pumping enables observing an electromotive force produced by the inverse spin Hall effect (ISHE) of SLG. The spin Hall angle of SLG is estimated to be 6.1 x 10(-7). The observed ISHE in SLG is ascribed to its non-negligible spin-orbit interaction in SLG. (C) 2014 AIP Publishing LLC.