Resist composition, method for forming resist pattern, compound, and acid diffusion control agent

A resist composition which generates an acid upon light exposure and whose solubility in a developing solution is changed by an action of the acid, the resist composition comprising:

• a base material component (A) whose solubility in a developing solution is changed by the action of the acid;
• and
• a compound (D0) represented by General Formula (d0),
• wherein Z represents a monocyclic group of a heterocyclic ring comprising at least a carbon atom and a nitrogen atom, nz0 represents an integer of 1 or greater as long as a valence is allowed, when nz0 represents 1, Yd01 represents a single bond or a divalent linking group, when nz0 represents 2 or greater, Yd01 represents an (nz0+1)-valent linking group, Yd00 represents a single bond or a linking group having 1 to 20 carbon atoms, Xd0 represents an iodine atom or a bromine atom, nxd0 represents an integer of 1 or greater as long as the valence is allowed, when nxd0 represents an integer of 2 or greater, a plurality of Xd0's may be the same as or different from each other, Rd0 represents a substituent other than Xd0, nrd0 represents an integer of 0 or greater as long as the valence is allowed, Mm+ represents an m-valent organic cation, and m represents an integer of 1 or greater.