M85 is a peculiar S0 galaxy in Virgo and is a well-known merger remnant . In this paper , we present the first spectroscopic study of globular clusters ( GCs ) in M85 . We obtain spectra for 21 GC candidates and the nucleus of M85 using the Gemini Multi-Object Spectrograph on the Gemini North 8.1 m telescope . From their radial velocities , 20 of the GCs are found to be members of M85 . We find a strong rotation signal of the M85 GC system with a rotation amplitude of 235 km s ^ { -1 } . The rotation axis of the GC system has a position angle of about 161 \arcdeg , which is 51 \fdg 5 larger than that of the stellar light . The rotation-corrected radial velocity dispersion of the GC system is estimated to be \sigma _ { r,cor } = 160 km s ^ { -1 } . The rotation parameter \Omega R _ { icor } / \sigma _ { r,cor } of the GC system is derived to be 1.47 ^ { +1.05 } _ { -0.48 } , which is one of the largest among known early-type galaxies . The ages and metallicities of the GCs , which show the same trend as the results based on Lick indices , are derived from full spectrum fitting ( ULySS ) . About a half of the GCs are an intermediate-age population of which the mean age is \sim 3.7 \pm 1.9 Gyr , having a mean [ Fe/H ] value of –0.26 . The other half are old and metal-poor . These results suggest that M85 experienced a wet merging event about 4 Gyr ago , forming a significant population of star clusters . The strong rotational feature of the GC system can be explained by an off-center major merging .