To provide a release fluid for an anisotropically electroconductive film which is excellent in the ability to release the residual cured film remaining around a terminal and does not attack the metallic terminal and the surrounding ordinary area.

The release fluid for the anisotropically electroconductive film comprises 40 mass% or more (a) -butyrolactone, 0-60 mass% (b) water or organic solvent such as ethylene glycol, 0-1 mass% (c) carboxyl-containing polymer, and (d) a neutralizing agent, such as triethanolamine, in such an amount as to reach a pH at which the carboxyl-group-containing polymer exhibits a thickening effect.