A photosensitive resin composition and a photosensitive dry film which are excellent in both sensitivity and stability and are well-balanced in tent strength, resolution and plating non-staining are provided. The photosensitive resin composition comprises an alkali-soluble resin (A), a photopolymerizable compound (B) and a photopolymerization initiator (C), and the polymerization initiator (C) comprises a hexaarylbisimidazole based compound (C1) and a multifunctional thiol compound (C2) as essential components. The photosensitive dry film has at least a photosensitive resin layer formed from the photosensitive resin composition on a support film.