Definitive diagnosis and early start of treatment cannot be made for tuberculosis since conventional methods for detecting a Mycobacterium tuberculosis complex require a long time plus enormous labor and expense. Because detection is difficult to perform directly from a biological sample, if the biological sample contains no or a very small amount of the Mycobacterium tuberculosis complex-specific secretory protein, there is a risk infection with the Mycobacterium tuberculosis complex will be missed. The present method and a kit address these long-standing needs by more rapidly and conveniently detecting a Mycobacterium tuberculosis complex, without culturing a biological sample containing the Mycobacterium tuberculosis complex, in which a biological sample is subjected to a heat-treatment so as to extracellularly secrete a Mycobacterium tuberculosis complex-specific secretory protein, such as at least one of MPB70, ESAT-6, or CFP-10 and subjecting the resulting treated sample to an immunological measurement/assay.