This invention provides a testing chip for the analysis of a sample, comprising (1) a reagent receiving part for previously receiving an aqueous reagent, (2) a mixing/reaction flow passage for conducting a series of operations consisting of mixing and reacting a sample and an aqueous reagent and detecting the reaction, and (3) a liquid feed control unit provided between an outlet flow passage in the reagent receiving part and an inlet in the mixing/reaction flow passage. The liquid feed control unit comprises a fine passage having a smaller flow passage sectional area than the outlet flow passage in the reagent receiving part and the inlet in the mixing/reaction flow passage. In the reagent receiving part, an aqueous reagent, a oil liquid, and an aqueous liquid having a larger surface tension than the aqueous reagent are disposed in that order toward the outlet flow passage. The aqueous liquid is received so as to come into contact with the liquid feed control unit, and the aqueous liquid is passed through the fine passage in the liquid feed control unit by applying a higher liquid feed pressure than a predetermined pressure to the reagent receiving part.