Provided is a pressure-sensitive adhesive (PSA) sheet having a low relative dielectric constant, satisfactory metal corrosion preventing property, and excellent member holding performance. The present invention provides a PSA sheet having a PSA layer including a base polymer and a rust inhibitor. The base polymer is an acrylic polymer, and monomeric components constituting the acrylic polymer comprise a (meth)acrylate having an alkyl group having 5 or more carbon atoms at an ester end at 50% by weight or more of the monomeric components. The PSA layer has a relative dielectric constant of 3 or less at 300 kHz.