Abstract: A tubular flow type reactor comprising: (1) inflow channels for respective inflow of at least two kinds of fluids to be used in a reaction, (2) an outer tube having a lumen that is capable of merging the fluids and of distributing the merged fluids for the reaction, (3) an outflow channel for outflow of a reaction product from the outer tube, and (4) an inner tube disposed in the lumen of the outer tube, wherein an annular flow channel is formed between the outer tube and the inner tube, and the inflow channels are connected to the outer tube along the direction tangential to the internal circumference of the outer tube in such a manner that the lumens of the inflow channels communicate with the lumen of the outer tube, i.e., the annular flow channel.