Helium plasma irradiation to metals could be a potential novel surface modification method in nanoscale. In this study, systematic helium plasma irradiations to titanium were conducted in low ion energy (< 100 eV) and high fluence (> 10(25)m(-2)) regime. From the surface analysis by scanning electron microscopy and transmission electron microscopy, various types of morphology changes, i.e. nanocone, pinhole, porous structure, and rough surfaces, were identified. The experimental conditions that control the various morphology changes are revealed from the aspect of the incident ion energy and the surface temperature. Based on the observations, it is thought that helium bubble growth, surface diffusion, and physical sputtering played important roles for the morphology change. (C) 2014 Elsevier B. V. All rights reserved.