There is provided an inspection method for a fuel cell or a fuel cell stack that ensures performing a leakage inspection minutely in a shorter time compared with the conventional inspection. The inspection method includes an enclosing step, an external leakage inspection step, and a communication leakage inspection step. The enclosing step encloses a first gas passage, a second gas passage, and a refrigerant passage in the fuel cell or the fuel cell stack to form three sections. The three sections are a first section, a second section, and a third section independent of one another. The external leakage inspection step simultaneously supplies an inspection gas to two or more sections among the three sections for pressure boosting to perform an inspection for leakage of the inspection gas from the two or more sections after boosting pressures to an outside. The communication leakage inspection step decompresses one section among the two or more sections after boosting the pressures and maintains a pressure of another one section or pressures of other two sections to perform an inspection for leakage of the inspection gas from the pressure-maintained one section or two sections to the decompressed one section.