<p>A storage device is made smaller and thinner so that IC memory card can be substituted by the storage device. When the recording medium cartridge is inserted into the frame, a slide member in a hub moves parallel to the frame and presses down a shaft under a restriction of a restriction member provided in the recording medium cartridge so that the hub and the shaft engages. When the recording medium cartridge is ejected from the frame, the slide member moves parallel to the frame and presses down the shaft under a restriction of the restriction member provided in the recording medium cartridge so as to release the engagement of the shaft and the hub. <IMAGE></p>
