PROBLEM TO BE SOLVED: To obtain a transgenic plant for highly accumulating a free amino acid in an edible part of plant, especially at least one amino acid of glutamic acid, asparagine, aspartic acid, serine, threonine, alanine and histidine and to provide a method for producing the same. SOLUTION: A glutamate dehydrogenase(GDH) gene together with a proper control sequence for expression in a plant cell is transduced into a plant. The GDH gene is overexpressed.