One mode of the present invention relates to a small-sized electronic casing comprising an aluminum alloy extruded shape having a hollow sectional part at least contained in a main part, wherein the extruded shape has at least either component-mounting holes or notches. Another mode of the present invention relates to a small-sized electronic casing manufacturing method that comprises a press punching process of forming at least either component-mounting holes or notches in an aluminum alloy extruded shape of a prescribed length having a hollow sectional part. The present invention may provide an aluminum alloy casing that is excellent in formability and productivity, has a smaller thickness and provides higher dimensional precision.