PROBLEM TO BE SOLVED: To provide: an acrylic adhesive that can prevent decrease of tenacity even if adhesion and release to/from skin are repeated; and an acrylic skin adhesive tape comprising the acrylic adhesive.SOLUTION: An acrylic adhesive is such that in an infrared absorption spectroscopy, a ratio [(B/A) ×100] of absorption strength B of 3,100-3,600 cmto absorption strength A of 1,600-1,800 cmis 40-80%. An acrylic skin adhesive tape includes: a base material; and an adhesive layer by the acrylic adhesive on the base material.