There is provided a content data reproducing system that allows, in a user terminal adapted to be able to read a recording medium storing a content data encrypted with a predetermined encrypted key data, the content data to be reproduced after a CM data is reproduced. The system includes a CM data transmission portion that transmits the CM data to the user terminal in response to a request from the user terminal. When the sensing portion senses that the reproducing of the CM data has been completed in the user terminal, a permission portion permits the user terminal to use the encrypted key data to decrypt and reproducing the content data.