High-pressure technique is a practical method for laboratory organic synthesis since simple equipment has become available in this decade. Pressure accelerates reactions if their values of 'the volume of activation' are negative, such as cycloaddition reactions and reactions through dipolar transition states. Especially, this technique is useful to drive reactions with steric hindrance. In this article are reviewed recent developments of substitution reactions, addition reactions to a carbonyl group, conjugated addition reactions, Deils-Alder reactions, 1, 4-cycloaddition reactions, other pericyclic reactions, and organometallic reactions since 1985.