Optical low-dispersion spectroscopic observations of Comet 103P/Hartley 2 at Koyama Astronomical Observatory during the EPOXI flyby

► We observed Comet 103P/Hartley 2 by the LOSA/F2 at KAO during the EPOXI flyby. ► We measured the mixing ratios of CN, C3, C2 and NH2 with respect to water. ► Resultant mixing ratios of radicals put the comet into the normal group in chemical composition. ► The slope of dust color was 13 ± 1%/1000 Å based on Afρ (cm) values at 5250 and 6250 Å. ► Our results suggests that Comet 103P/Hartley 2 is a typical (non-depleted) comet.