Abstract: A reagent reaction apparatus for automatically performing a reaction by introducing various kinds of reagents to a sample solution. The reagent reaction apparatus includes a number of sample vials within a containing section and a plunger valve with fluid introducing port and a fluid discharge port located on top of the containing section. A mechanism sequentially injects into the sample vial a predetermined amount of reagents into a sample vial containing a measured amount of sample solutions. The sample vial is held in a rotary cone in order to apply centrifugal force. Then, the sample solution and reagents are subjected top a temperature adjusting bath which is preselected for the required reaction temperature. A mechanism transports the final product in the sample vial to a discharge station.