A card reader with multiple slots to convert data stored in electronic cards in different format into the interface format of Express Card™ and to output the converted data to a computer includes an insulation casing, two slots, one Express Card™ connector, and data relay unit to convert the data storage format of an electronic card into the interface format of Express Card™ and to output the converted data through the Express Card™ connector; each slot being divided into multiple terminal sets to respectively connect to multiple electronic cards for reducing the space of the card reader, facilitating portability, and better adapting to expansion medium used by mobile commerce or traveler.