Carbon nanotubes (CNTs) have been attracting attention because of their prominent mechanical and electronic properties. In this study, we investigate the deformation of a single-walled carbon nanotube (SWCNT) with a bend junction using atomistic modeling with Brenner potential to analyze strain concentration caused by macroscopic tube shape and microscopic interatomic bond structure. The simulation model consists of (8,8) and (14,0) CNTs connected with a flexion angle of 30 degrees. For geometric reasons five and seven-membered rings are introduced at the inside and outside of the bend junction. After the structure under no external load is determined, tensile load is applied to the model. Then, we analyze the strain concentration at the bend junction, and high tensile strain is observed at the inside of the bend junction. The strain at the seven-membered ring at the inside of the bend junction has higher strain compared to the neighboring rings due to the microscopic effect.