A medical diagnostic instrument is provided. The medical diagnostic instrument may be used with a tongue depressor. The medical diagnostic instrument includes an illumination module, an installation structure and a top bracing structure. When the tongue depressor presses on the tongue base of the patient, the illumination module provides illumination to the diagnostic area within the patient's oral cavity, so as to facilitate the diagnosis of patient’s oral cavity.一種醫療診斷器械，係結合壓舌板使用，主要包括本體，以及設於本體上的照明模組、裝設結構與朝上頂撐結構，俾於該壓舌板按壓該患者的舌根部時，令該照明模組對該患者口腔內的診斷區域提供照明，從而便於針對患者的口腔進行診斷。
