Actinic-ray-sensitive or radiation-sensitive resin composition, resist film, pattern forming method, and method for manufacturing electronic device

An actinic ray-sensitive or radiation-sensitive resin composition comprising:

• a resin (A) including a repeating unit having an acid-decomposable group;
• and
• a resin (B) including a repeating unit having an acid-decomposable group,
• wherein an absolute value |GA−GB| of a difference between a mole-based content ratio GA of the repeating unit having an acid-decomposable group in the resin (A) and a mole-based content ratio GB of the repeating unit having an acid-decomposable group in the resin (B) is from 5% by mole to 20% by mole,
• the acid-decomposable group in the resin (A) and the acid-decomposable group in the resin (B) have the same structures,
• a ratio SA/SB between a mass-based content ratio SA of the resin (A) to a mass-based content ratio SB of the resin (B) with respect to a total solid content in the actinic ray-sensitive or radiation-sensitive resin composition is 10/90 to 90/10,
• an absolute value |MwA−MwB| of a difference between a weight-average molecular weight MwA of the resin (A) and a weight-average molecular weight MwB of the resin (B) is from 1,000 to 5,000,
• an absolute value |MwA/MnA−MwB/MnB| of a difference between a molecular weight distribution MwA/MnA of the resin (A), which is a value obtained by dividing MwA by a number-average molecular weight MnA of the resin (A), and a molecular weight distribution MwB/MnB of the resin (B), which is a value obtained by dividing MwB by a number-average molecular weight MnB of the resin (B), is 0.05 or more, and
• the repeating unit having an acid-decomposable group included in the resin (A) and the resin (B) is represented by General Formula (Aa2),
• in General Formula (Aa2), R101 represents a hydrogen atom, a fluorine atom, an iodine atom, an alkyl group, or an aryl group, and R102 represents a group that leaves by an action of an acid.