Conventional methods for detecting a Mycobacterium tuberculosis complex require a long time and also require enormous labor and expense. Thus, definitive diagnosis and early start of treatment cannot be made for tuberculosis, and there has been a demand for a rapid detection method. The detection is difficult to perform directly from a biological sample, if the biological sample contains no or a very small amount of MPT64. As a result, infection with the Mycobacterium tuberculosis complex might be missed. Thus, there has been a need for a more reliable detection method. The present invention provides a method and a kit for more rapidly and conveniently detecting a Mycobacterium tuberculosis complex without culturing a biological sample containing the Mycobacterium tuberculosis complex, comprising subjecting the biological sample to a heat-treatment so as to extracellularly secrete a Mycobacterium tuberculosis complex-specific secretory protein, particularly, MPB64, and subjecting the resulting treated sample to an immunological assay.