An object of the present invention is to provide a method for producing PHA capable of providing PHA (for example, a PHA powder) having excellent thermal stability with high productivity. The present invention is a method for producing polyhydroxyalkanoic acid, the method including a step (a) and a step (b) below: step (a) of preparing an aqueous suspension liquid containing polyhydroxyalkanoic acid and polyvinyl alcohol and having a pH of 7 or less; and step (b) of spray-drying the aqueous suspension liquid prepared in the step (a).