In a conventional content transmission system, there has been a problem that it takes a long time from when a user, who tries to start viewing and listening of content, issues a command to a receiver by using a remote controller or the like until when the user can actually view and listen to the content from content viewing and listening equipment (content starting time). To this end, a content transmission system according to the present invention has a transmitter and a receiver including a human sensor and has a configuration that the state of the receiver is changed corresponding to a detection result of the human sensor so as to reduce the content starting time and power consumption.