A sample solution introduction kit and a sample solution injector capable of introducing sample solution while reducing the rate of occurrence of an air bubble and having a simplified structure are proposed.A sample solution introduction kit includes a plate-like member and a sample solution injector. The plate-like member has a plurality of spaces formed therein and serving as reaction field and a communication space that communicates with the plurality of spaces therein and that has a portion defining an opening formed in a surface of the plate-like member, and the sample solution injector includes a container containing the sample solution, a tube that communicates with the bottom of the container and that is insertable into the opening, a stopper removably fitted into an opening formed at a top end of the tube, and liquid held in the container, and the liquid is insoluble in the sample solution and is lighter than the sample solution.