Adhesive composition, adhesive layer, optical film having attached adhesive layer, optical member, and image display device

The present invention pertains to an adhesive composition containing a rubber-based polymer (A) and a tackifier (B), wherein the rubber-based polymer (A) includes at least one rubber-based polymer selected from the group consisting of a styrene-based thermoplastic elastomer (A1) and an isobutylene-based polymer (A2) having a weight average molecular weight of 500,000 or greater. The rubber-based polymer includes at least one selected from the group consisting of a natural material-based tackifier (B1), a petroleum resin-based tackifier (B2) and hydrogenated products thereof, when including the styrene-based thermoplastic elastomer (A1); and includes at least one selected from the group consisting of a natural material-based tackifier (B1) and hydrogenated products thereof, when including the isobutylene-based polymer (A2). This adhesive composition has low moisture permeability, and is capable of forming an adhesive layer which, even in high-temperature environments, is durable enough not to suffer from probl