Microanalysis chip

The problem addressed by the present invention is to provide a microanalysis chip capable of stably measuring ion concentration without enlarging the chip size or increasing the measurement time. In order to solve this problem, the following microanalysis chip is provided. In other words, the microanalysis chip has a reference electrode arranged in a first channel chamber, an ionic crystal which is arranged on the surface of the reference electrode and which can be dissolved in the sample, and a working electrode arranged in a second channel chamber, when the average area velocity, which is the area of a region in which the sample permeates per unit time in the surface of the porous substrate, is defined as V1 before the distributed sample reaches the reference electrode, and when the average area velocity, which is the area of a region permeated by the sample per unit time in the surface of the porous substrate, is defined as V2 after the distributed sample reaches the reference electrode and before the firs