The present invention provides a content data retrieval apparatus capable of appropriately narrowing down the range of search targets even in the case where a distribution of attribute values of a group of contents regarded as search targets is uneven.The content data retrieval apparatus of the present invention includes: an impression value database which stores attribute values; a conversion table in which an impression value is associated with a search word range that is a range of the attribute values associated with a search word; a range modification unit which modifies a relative relationship between a distribution range of attribute values and a search word range by modifying the search word range read out from the conversion table; a receiving unit which receives an input of a search word; and a retrieval unit which retrieves content data corresponding to the search word received by the receiving unit, by searching the attribute values included in the search word range associated with the search word.