The estimation of fatigue reliability at elevated temperatured for advanced carbon fiber reinforced PA46 was examined. Especially meso crack forming stage developed on notch bottom and its effect on fatigue reliability at elevated temperature. The main results are as follows, (1) The fatigue strenght, life of crack initiation and life of crack propagation for V-notch specimens were almost the same at elevated temperature. (2) From fractography using SEM, it was recognized that the matrix was elongated and the cementing of the interface between fiber and matrix was poor. So it was thought that the crack propagation resistance at elevated temperature was not influence by the kinds of fiber. (3) It was considered that the difference of crack tip heat change accompanying fatigue damage and crack propagation was controlled under the linear fracture mechanics.