Provided are a masking film and masking film support for plating that have the ability to adjust well to circuit patterns, and that exhibit superior thermal dimensional stability, high plating formation precision, and superior punch workability. The masking film support is obtained by adding a clay mineral, which serves as an inorganic filler, to a polybutylene terephthalate film, and the masking film support has a tensile modulus of 700-5000MPa at a temperature of 23°C. An adhesive layer is provided to one surface of the masking film support. The content of the clay mineral is 10-40 mass parts relative to 100 mass parts of a resin component included in the polybutylene terephthalate film.