The present disclosure relates to a shell-and-multi-double concentric-tube reactor and a shell-and-multi-double concentric-tube heat exchanger, and to a shell- and-multi-double concentric-tube reactor and a shell-and-multi-double concentric-tube heat exchanger which provide a new type of reactor and a heat exchanger, thereby maximizing catalyst performance and improving performance of the reactor by optimizing heat exchange efficiency and a heat flow, uniformly distributing a reactant, and increasing a flow rate of the reactant, and accordingly making the reactor and the heat exchanger compact.