The present invention relates to a flash memory card that is a structure using a rigid flexible board (RFB) to connect a flash memory card unit and a universal serial bus (USB) unit. A communication interface in compliance with the specification of the flash memory card is disposed at one end of the flash memory card, and a USB communication interface is disposed at another end, and a rigid flexible board is provided for connecting the electric signals between the two communication interfaces and the bending characteristic is used to maintain the height difference between the planes of the two communication interface, so that the flash memory card can concurrently have the USB communication interface and enhance the applicability of the flash memory card.