A sheet feeder includes a recording media storage device. The recording media storage device stores recording media and is attachable to and detachable from a main body of an image forming apparatus. The image forming apparatus includes a feeding mechanism to pick up and convey one of the recording media at a time. The lock member disables the recording media storage device to be detached. The overflow restriction member is disposed in the main body and changes between a restriction position closer to an uppermost part of the recording media and a withdrawal position farther from the uppermost part of the recording media. The position change mechanism is disposed in the main body and changes the overflow restriction member into the restriction position when the lock member changes into a free state in which the recording media storage device is attachable and detachable.