MOBILE OBJECT CONTROL DEVICE, MOBILE OBJECT CONTROL METHOD, AND STORAGE MEDIUM

A mobile object control device of an embodiment includes a partition line candidate recognizer that recognizes candidates for partition lines for partitioning a traveling lane in which a mobile object travels from a first image including the vicinity of the mobile object captured by an image capturer, and a partition line searcher that selects a partition line candidate closest to a past partition line for partitioning the traveling lane of the mobile object before a predetermined time, among the partition line candidates recognized by the partition line candidate recognizer, as a partition line for partitioning a current traveling lane of the mobile object.