A method of analyzing ions adsorbed on a surface of a mask for pattern formation of a semiconductor device, and an apparatus using the same are disclosed. The ion analyzing method includes: filling a heating container within a main chamber with a predetermined amount of a solvent; immersing a mask in the solvent-filled heating container; raising an internal pressure of the chamber to a predetermined level by supplying gas into the chamber; separating ions from a surface of the mask by heating the solvent within the heating container at a predetermined temperature for a predetermined period; and analyzing the ions by collecting the solvent.