Abstract: Provided are a multiple immunoassay apparatus on a chip in which a structure comprising multiple microfluidic channels is associated with a tissue sample, which allows immunohistochemical reactions to be conducted therein, to examine various markers specific for certain diseases, and a method for performing multiple immunoassays using the same. The multiple immunoassay apparatus comprises: at least one antibody-introducing unit through which at least one antibody is introduced into the apparatus; at least one reaction unit in which the antibody reacts with a sample in an immunohistochemical pattern; and at least one fluid outlet through which a fluid including the antibody is discharged outside the apparatus.