A structural change has been found in PrRu4P12 accompanied by a metal-insulator transition at about 60 K by electron diffraction. At room temperature the structure of Filled-Skutterudite type compound PrRu4P12 belongs to space group Im3 (No.204), and is a metal. At about transition temperature new and weak reflections appear at h + k + 1= 2n + 1 positions. Space group and structure of the low temperature phase is discussed to be P23 (No. 195) or Pm3 (No.200) . The origin of the transition was discussed.
