It is unclear whether the effects of emotional state on working memory (WM) are valence-based or motivation-based since the type of emotions used in previous research differed on both dimensions of emotion. Especially, effects of anger, which is a negative but approach-related emotional state, were mostly overlooked. To distinguish between valence vs. motivation accounts, two experiments were conducted in which participants were induced one of four emotional states to create approach-positive (happiness), avoidance-negative (fear), approach-negative (anger), and control (neutral) conditions, followed by Self-ordered Pointing Task (Experiment 1) or N-Back task (Experiment 2) as WM measures. The main effect of emotion on WM accuracy was not significant in neither experiment. In the second experiment, however, reaction times (RTs) in the avoidance-related emotion condition were significantly faster compared to those in approach-related conditions, without compromising accuracy. Together the two experiments suggest that the motivational dimension of emotional state is more effective on WM than the valence dimension, especially on the RTs, indicating working memory updating efficiency.