In this study, hoarding tendencies were defined as the trait through which many possessions were accumulated and could not be discarded because of their subjective meaning. Two internet surveys were conducted. In Study 1, a hoarding tendency scale for non-clinical individuals was developed, with questionnaires sent to 410 participants. In Study 2, animistic thinking was taken up as one of the determinants of hoarding, and the relationship between animistic thinking and hoarding tendencies was investigated. Two hundred and thirty-four participants were asked to complete a questionnaire. The main findings were as follows: (1) The results of factor analysis indicated that the hoarding tendency scale consisted of six factors (28 items), such as “having too many things” and “avoidance of discarding things.” These subscales indicated the common and particular attitudes of hoarders toward their possessions. (2) The hoarding tendency significantly correlated with compulsive buying. This result indicated that the hoarding tendency scale demonstrated sufficient criterion-related validity. (3) Animistic thinking, especially “part of the possessor” and “the anthropomorphication of possessions,” had a significant effect on hoarding tendencies.