The glutamate transporter EAAT4 is expressed specifically in cerebe llar Purkinje cells (PCs), and localized at PC spines synapsing with parallel fibers or climbing fibers. In this study, we analyzed its precise localization in the PC spine by immunogold techniques with antibodyagainst the N-terminal sequence. Colloidal golds enhanced by silver for the EAAT4 were localized in the extrasynaptic membrane of PC spines, not the synaptic membrane facing presynaptic terminals. The localization suggests that the glutamate transporter EAAT4 is involved in glutamate uptake at extrasynaptic sites, which may facilitate the transmitter diffusion from the synaptic cleft.