Active light sensitive or radiation sensitive resin composition, pattern forming method, method for manufacturing electronic device, and electronic device

An actinic ray-sensitive or radiation-sensitive resin composition comprising a resin (P) including a repeating unit (i) having a group which decomposes by the action of an acid represented by the following General Formula (1):

• in General Formula (1), R1 represents an alkyl group having 2 or more carbon atoms, R2 represents an alkyl group having 2 or more carbon atoms, and Z represents a group that forms a monocyclic structure together with a carbon atom.