The first high pressure study on a fast inorganic reaction was reported by Brower in 1968. Since then, various high pressure apparatus for the study of fast reactions in solution, such as high-pressure T-jump, P-jump, NMR, stopped-flow, etc., have been exploited with the increasing interest in the high pressure chemistry of fast inorganic reactions. In this review, after brief explanations of the apparatus and classification, the relation of activation volumes and complex formation and solvent exchange mechanisms of metal ions classified by the Langford and Gray classification, which is assigned on the basis of kinetic data at ambient pressure, is explained. Recent studies relevant to high pressure kinetics are also covered.