Maladaptive perfectionists tend to set high standards for academic tasks, even if they cannot achieve their standards. How do they sustain high academic motivation? The present study investigated the mediators affecting high academic motivation observed in maladaptive perfectionists. We examined the relationships between perfectionism, contingent self-worth, rumination about failure, and motivation for daily academic tasks in undergraduates (N=185). Multiple mediational analyses indicated that perfectionistic strivings positively and directly affected achievement motivation. Activity-based self-worth marginally mediated between perfectionistic strivings and achievement motivation through competition. Moreover, perfectionistic concerns negatively and directly affected achievement motivation through self-fulfillment, and positively and directly affected failure-avoidant motivation. Rumination about failure significantly mediated between perfectionistic concerns and failure-avoidant motivation. These results suggest that the high academic motivation observed in maladaptive perfectionists is mediated by activity-based self-worth and rumination about failure.