A positive-tone radiation-sensitive resin composition containing an anthracene-based carboxylic acid component with low sublimation properties and excellent compatibility with other components is provided. The composition exhibits optimum controllability of radiation transmittance as a chemically amplified positive-tone resist effectively responding to active radiation, particularly to deep ultraviolet rays, effectively controlling line width variation in resist patterns due to fluctuation in the resist film thickness on a highly refractive substrate, and exhibiting excellent focal depth allowance. The composition comprises (A) an anthracene derivative of the following formula (1), (B) a photoacid generator comprising a sulfonimide compound, and, (C) a resin containing an acid-dissociable group, wherein R.sup.1 is a hydrogen atom or a monovalent organic group, R.sup.2 is a monovalent organic group, e is an integer of 0-3, and f is an integer of 0-8. The metal impurity content in the component (A), in terms of the total ion content, is preferably 5,000 ppb or less.