Motivation, which is considered to have a significant impact on human behavior, can be arranged along a continuum based on the degree of self-determination, according to the sub-theory of Self-Determination Theory known as Organismic Integration Theory. This continuum includes intrinsic motivation, extrinsic motivation, and other forms, with varying degrees of self-determination. Traditionally, the degree of self-determination has been measured subjectively, often through questionnaires. Therefore, this study aimed to objectively measure the degree of self-determination in motivation by examining the relationship between physio-logical indicators and self-determined motivation. As the experiment, participants engaged in tasks with using a personal computer to search for information and create materials. During these tasks, physiological indicators were measured, and the degree of self-determined motivation was assessed using an existing questionnaire that inquired about the reasons for performing the tasks. Based on the collected data, the study elucidated the correlation between some psychophysiological indices and the degree of self-determined motivation.