Abstract: The present invention provides an all-in-one type continuous reactor for preparing a positive electrode active material for a lithium secondary battery. The continuous reactor includes a flange unit provided at one side of a cylinder; at least one reactant inlet port provided on the flange unit; a reaction product outlet port provided at the other side of the cylinder; a plurality of extra ports provided between the reactant inlet port and the reaction product outlet port; a temperature control unit disposed between an inner circumferential surface and outer circumferential surface; a pulverizing unit provided in the reactant inlet port; a flow rate sensor provided in at least one of the reactant inlet port; and a flow rate control unit configured to control the flow rate of the reactant.