In works of tunnel excavation, it is constantly required to estimate the stability of cavern based on in-situ measuring data. The present paper describes a simple method for deciding Young's modulus of rock mass and the directions of applied initial stresses in the ground and their values, graphically, using nomographs calculated by exact elastic solutions. As the analytical theory for nomographs, the complex variable method with conformal mapping transformation developed by the authors is used, and the nomographs take complete consideration of a characteristics of displacement in the ground such as pre-displacement occurring before setting NATM measuring pins. The poisson's ratio of rock mass is assumed to be 0.25 in these homographs. The influence of variation of in-situ rock elasticity and the setting error of measuring pins are additionally discussed in this paper.