Magnesium alloy plate and magnesium alloy member

Provided are a magnesium alloy plate which is excellent in terms of workability concerning plastic working, e.g., pressing, and a magnesium alloy member. The magnesium alloy plate is a plate obtained by rolling a magnesium alloy and has a cross section which is parallel with the thickness direction thereof and in which if the crystal grains present in the cross section are each examined for major-axis length and minor-axis length and for aspect ratio, which is the ratio of the major-axis length to the minor-axis length, i.e., (major-axis length)/(minor-axis length), and if the crystal grains having an aspect ratio of 3.85 or higher are taken as elongated grains, then the area fraction of the elongated grains in the cross section is 3-20%.