Provided are a PHA-producing microorganism producing a higher molecular weight PHA and a PHA production method using the PHA-producing microorganism. A PHA-producing microorganism including a gene encoding a PHA synthase derived from genus Aeromonas, in which at least a portion of a PHA degrading enzyme gene is altered by substitution, deletion, insertion, and/or addition to reduce or eliminate activity of a PHA degrading enzyme encoded by the gene, and further a glycerol kinase activity is enhanced.