PROBLEM TO BE SOLVED: To obtain an area where the measurement of the size of an object is facilitated.SOLUTION: A distal end 21 captures images of a subject and outputs imaging signals. A CPU 18 measures the size of the subject on the basis of imaging signals to be output from the distal end 21. An LCD 5 displays images. An image signal processing circuit 12 allows the LCD 5 to display live images that are obtained by overlapping measurable area displaying that indicates areas where the CPU 18 can measure the size of the subject with images based on imaging signals.