A planetary gear train for an automatic transmission may include input shaft, output shaft, first to fourth planetary gear sets and seven friction elements disposed to selectively connect the rotation elements with the rotation element and selectively connect the rotation elements with a transmission housing, and wherein the input shaft is/are continuously connected to the second rotation element, the output shaft is/are continuously connected to the eleventh rotation element, the third rotation element is/are continuously connected to the fifth rotation element, the third rotation element is/are continuously connected to the tenth rotation element, the fourth rotation element is/are continuously connected to the ninth rotation element, the sixth rotation element is/are continuously connected to the seventh rotation element, the input shaft is/are selectively connected to the sixth rotation element, wherein three friction elements among seven friction elements is/are operated at each speed stage.