A mobile leakage detecting device according to the present invention is provided for simplifying detecting operations of a leak portion and enhancing operational efficiency, and is characterized by microphones for detecting ultrasonic waves generated at a fluid leak portion, an input device for inputting positional information of the leak portion in a searching area detected based on output signals from the microphones, a photograph device for photographing the leak portion, a display device for indicating the positional information inputted by the input device and photographed image information of the leak portion obtained by the photograph device and data processing device for relating with one another and storing the output data from the microphones, positional information inputted by the input device and photographed image information obtained by the photograph device on the same leak portion.
