Resist composition and method of forming resist pattern

A resist composition which generates acid upon exposure and exhibits changed solubility in a developing solution under action of acid, the resist composition comprising:

• a base material component (A) which exhibits changed solubility in a developing solution under action of acid,
• an acid-generator component (B) which generates acid upon exposure, and
• a basic component (D) which controls diffusion of the acid generated from the acid-generator component (B) upon exposure,
• the basic component (D) comprising a compound (D0) represented by general formula (d0) shown below, and
• a total amount of the acid-generator component (B) and the basic component (D) being 25 to 60 parts by weight, relative to 100 parts by weight of the base material component (A):
• Rd0-Xd0-Yd0-COO⊖(Mm⊕)1/m (d0)
• wherein Rd0 represents a monovalent organic group;
• Xd0 represents —O—, —C(═O)—, —O—C(═O)—, —C(═O)—O—, —S— or —SO2—;
• Yd0 represents a single bond or a divalent hydrocarbon group which may have a substituent;
• Mm+ represents a m-valent organic cation;
• and m represents an integer of 1 or more.