The present invention provides a magnesium alloy material, having superior mechanical properties without using special production equipment or processes, and a production process thereof. The magnesium alloy material of the present invention composed of an Mg—Zn—RE alloy comprises essential components in the form of 0.5 to 3 atomic percent of Zn and 1 to 5 atomic percent of RE, with the remainder comprising Mg and unavoidable impurities. The Mg—Zn—RE alloy has a lamellar phase formed from a long period stacking ordered structure and α-Mg in the alloy structure thereof. The long period stacking ordered structure has at least one of a curved portion and a bent portion and has a divided portion in at least a portion thereof. Finely granulated α-Mg having a mean particle diameter of 2 μm or less is formed in the divided portion.