An object of the present invention is to provide a PHA-producing microorganism which can assimilate sucrose, and a method for producing a PHA by culturing this microorganism, using sucrose as a carbon source. A PHA-producing microorganism, comprising a PHA synthase gene, and heterogeneous-organism-derived genes in the following items (1) and (2): (1) a sucrose hydrolase gene encoding an amino acid sequence described in SEQ ID NO: 1, or a gene encoding a polypeptide which has a sequence homology of 90% or more to the amino acid sequence and which has sucrose hydrolase activity; and (2) a sucrose permease gene encoding an amino acid sequence described in SEQ ID NO: 2, or a gene encoding a polypeptide which has a sequence homology of 90% or more to the amino acid sequence and which has sucrose permease activity. The invention is also a method for producing a PHA, including the step of culturing this microorganism in a medium including sucrose as a carbon source.