The wood-boring beetle Platypus quercivorus (Murayama) (Coleoptera: Platypodidae) is a vector for the fungus that causes Japanese oak wilt. We hypothesized that volatiles emitted from leaves of trees are cues for P. quercivorus to distinguish host from non-host trees, and that olfactory response of P. quercivorus to leaf volatiles changes in the course of flight. Y-tube olfactometer bioassays were done for 54 beetles to test their olfactory responses to leaf volatiles emitted from host (Quercus crispula, Q. serrata, Q. salicina and Castanea crenata) seedlings and non-host (Fagus crenata and Cryptomerica japonica) seedlings. The bioassays were repeated 20 times, 10 times before and 10 times after flight in a flight mill, for each individual beetles. Further, components of leaf volatiles were analyzed using gas chromatography-mass spectrometry (GC-MS). Results of bioassays supported our hypothesis: P. quercivorus was attracted to the leaf volatiles of hosts and avoided the leaf volatiles of non-hosts, and the olfactory responses of P. quercivorus to the leaf volatiles increased after flight. Additionally, leaf volatile components of C. japonica clearly differed from those of the hosts. However, leaf volatile components of F. crenata were similar to those of the hosts. Results of GC-MS can partly explain the difference in olfactory response of beetles to leaf volatiles.