Disclosed is a polymer powder having an average particle diameter of 20 µm to 300 µm, with a particle diameter of less than 10 µm of 10 mass% or less, and a particle diameter of greater than 300 µm of 10 mass% or less. Further, disclosed is a method for preparing a polymer powder, comprising: forming a melt of a polymer; introducing a supercritical fluid into the melt of the polymer to form a mixed composition; and spraying the mixed composition to prepare the polymer powder.