A module for the synthesis of organic molecules on or in solid phase and an apparatus comprising at least such a module. The module consists of several synthesis reactors formed, each, by a tubular body forming a reaction chamber delimited in its lower part by a removable porous wall, designed to retain the synthesis support material, an injection and expanding head forming an upper closure plug for the tubular body, a closure and emptying base mounted removable in a lower extension of the tubular body. Each reactor is provided with a heat exchanger in close peripheral contact with the tubular body at least at the part of the chamber designed to contain the medium and the reaction compounds and a condenser in close peripheral contact with the body at the part of the chamber extending above that containing the medium and the reaction compounds and beneath the injection head.