The invention provides a radiation detecting device. The device comprises a detector shell, a detector, a main plate and a handle. The detector comprises a scintillation crystal and a photoelectric conversion device which are coupled to each other. The main plate and the photoelectric conversion device are connected in a communication connection mode, the main plate and the detector are arranged in the detector shell, the handle and the detector shell are connected and a battery chamber is arranged in the handle, a battery is placed in the battery chamber, and the battery is electrically connected to the main plate. The handle is provided with a battery chamber cover which is cooperated with the battery chamber, a sleeve is arranged outside the handle, and the battery chamber cover is located in the sleeve and abuts against the inner wall of the sleeve. The device comprises an adjusting mechanism and a protection cover. In the invention, multiple insurances are provided to solve a problem that the battery and the battery chamber cover are easy to fall off, and disassembly is convenient; a detection range is wide, a detection effect is better, and the protection cover is not easy tolose.