This study aims to investigate the difference in perceiving Korean accusative case markers ‘eul’ of Korean native speakers and L2 learners through a self-paced reading(SPR) task. The study employed 15 native speakers, 17 advanced learners with TOPIK level 6 and 16 intermediate learners with TOPIK level 4. Their SPR results were analyzed to find out the perception similar among three groups, but there is a delicate difference among them. As results the study found out that (i) intermediate learners showed the longer Reaction Time(RT) on the window 3 and 4 than other two groups and it seems that the proficiency influences on the RT, (ii) learners’ accuracy rate(ACC) showed the violation of syntax influences on the ACC and they noticed well in the sentence which has the correct syntax than wrong. Overall, advanced and intermediate learners in this study showed significant difference of perceiving accusative case markers compared to native speakers. (KyungHee University)