This study aimed to demonstrate experimentally that other-oriented motivation increases the amount of work. We reproduced a scene in which college students participate in part-time work in the laboratory and examined whether other-oriented motivation would lead to an increase in the amount of work in part-time jobs outside the specified time using Bayesian estimation. Findings revealed that participants with conditions that evoked other-oriented motivation would engage in more overtime part-time work than would participants in the control condition. It was suggested that other-oriented motivation increases the amount of work.