There is disclosed an image recording apparatus including: a housing; a medium supply cassette open upward which accommodates a stack of recording media each in the form of a sheet, and is inserted into and removed from the housing substantially horizontally in a cassette movement direction, the cassette including: a substantially horizontal bottom plate; and a slant separator plate extending obliquely upward from an edge of the bottom plate; a medium pickup device including a medium pickup roller which gives a feeding force in a first direction to a topmost one of the stack, and cooperates with the separator plate to separate the topmost recording medium from the rest of the recording media to feed in the separated recording medium; a U-shaped guide changing a feeding direction of the recording medium as fed in by the pickup device, from the first direction to a second direction opposite to the first direction; an image recording portion recording an image on the recording medium having been passed through the guide; and a restricting member contacting at least a part of the stack which ascends upward along the separator plate by continuing to move, by inertia, in a cassette insertion direction in which the cassette is inserted, in order to restrict the continuing movement of the at least a part of the stack.