A contents providing system for providing video contents through a social service includes a memory storing computer-readable instructions; and one or more processors configured to execute the instructions to, manage information on a social network between users of the social service; and provide a together-watching function if at least one conversation partner is selected from a list of different persons related to a user according to the social network, wherein the together-watching function is a function that provides simultaneous display of a conversation screen with the at least one conversation partner and a video reproduction screen in which the video contents are reproduced.