The purpose of this study was to investigate the resultant motivation of under achievers in arithmetic learning. The shimane Resultant Achievement Motivation Inventory in School Mathematics (Shimane AMIM) developed by Ito et al. was administered to 131 fifth and sixth graders. The Shimane-AMIM was constructed to measure both the tendercy to achieve success (P tendercy) and the tendency to avoid failure (N tendercy) in school mathematics. Main results obtained in this study were that under achievers have higher anxiety, but have as much desire for success in mathematics learning as high ability pupils.