A content sharing device includes a content acquisition circuit configured to acquire main content and sub-content, at least one of which is derived from digital ink, and a transmission processing circuit configured to, in response to receipt of a request made by a terminal device operated by a user, select either first provision data or second provision data depending on usage rights of the user and transmit the first or second provision data that has been selected to the terminal device. The first provision data includes only the main content, while the second provision data includes both the main content and the sub-content. The sub-content includes content generated using a plurality of content elements that are generated before the main content is published or content generated using a plurality of content elements that are generated after the main content is published.