The small size effect, aka the volume effect, refers the effect of that the number of atoms contained in the particle decreases when their size and volume become smaller. When the size of solid particles gradually decreases, especially as small as that of atom, their Van der Waals force gets stronger. The sound, light, electric, magnetic, heat, and chemical properties of the particles will change accordingly. Given such miniscule scale, the classical theory can no longer explain the entire phenomenon. The influence of small size effect has become significant. Furthermore, with the substantial increase in the proportion of surface area, matter will display the properties of physics, chemistry, and biology distinct from those at the macroscale. This study, therefore, will explore the sensitivity analysis of the small size to the attached mass and linear spring on the miniscule cantilever beam. The data observed in this study can be used as a reference for the future fields of industry and design.