PURPOSE: To well stir two substances to be stirred simultaneously and to also perform irregular stirring without bringing about problems in a manner such that constitution becomes complicated and an apparatus is made large-scaled, by integrally mounting two stirrers to a support.

CONSTITUTION: A stirring apparatus 9 equipped with a support 9a, the arm 9b integrally provided to said support 9a and motors 9c, 9d forming the principal parts of stirrers provided to the outside parts of the arm 9b revolves around the center of revolution set in an outer direction with respect to the circular track arranging the reaction tubes 1a of a reaction tube tray 1. The motors 9c, 9d of the stirrers respectively have stirring rods 9c1, 9d1. By the rotation (ON) of the reaction tube tray 1, the reaction tubes 1a, 1b successively move and the support 9a of the stirring apparatus 9 revolves (turns ON) to set the stirring rods 9c1, 9d1 to stirring positions. Whereupon, the reaction liquids of the reaction tubes 1a, 1b are simultaneously stirred.