Photosensitive resin composition, dry film, solder resist, and printed wiring board

The invention provides a photosensitive resin composition which can improve developability and deep curability even if titanium oxide is contained, and can improve the appearance and reflectivity of a solder resist layer. The photosensitive resin composition contains a carboxyl group-containing resin (A), a photopolymerization initiator (B), a photopolymerizable compound (C), an epoxy resin (D), and titanium oxide (E). The carboxyl group-containing resin (A) contains a vinyl polymer which has a carboxyl group-containing residue and an ethylenically unsaturated group in a side chain and has a weight-average molecular weight of 10,000-100,000, and the carboxyl group-containing resin (A) contains an oligomer moiety having a molecular weight of 450-1,000. The ratio of the titanium oxide (E) is 20 parts by mass or more with respect to 100 parts by mass of the carboxyl group-containing resin (A). 本发明提供一种感光性树脂组合物，其即便含有氧化钛，也能够提高显影性和深部固化性，并且能够提高阻焊层的外观和反射率。感光性树脂组合物含有：含羧基树脂(A)、光聚合引发剂(B)、光聚合性化合物(C)、环氧树脂(D)和氧化钛(E)。含羧基树脂(A