To provide an aluminum alloy plate member having an outward appearance of a hem part equally matched for the outward appearance of the hem part made of a steel plate.

This aluminum alloy plate member 1 having the hem part 25, is composed of an outer material 2 made of the aluminum alloy plate and an inner material 3 made of the aluminum alloy plate and fitted to the above outer material 2. In the tip end part of the hem part 25, the hem tip end part 255 has the outside curving radius R=1.0T-1.2T to the plate thickness T of the outer material 2. Further, in the hem tip end part 255, it is desirable that the above outer material 2 has the close-stuck part closely bent at 180°.