1. A stay condition analyzing apparatus that acquires stay information regarding a stay condition of a moving object within a target area, generates a heat map image obtained by visualizing the stay information, and displays the heat map image on a display device, the stay condition analyzing apparatus comprising: a processor; and a memory which stores an instruction, wherein as a configuration when the processor executes the instruction stored in the memory, the stay condition analyzing apparatus includes a stay information acquirer which acquires the stay information for each predetermined measurement period of time on the basis of positional information of the moving object which is acquired from a captured image of the target area, a heat map image generator which generates the heat map image obtained by visualizing the stay information acquired by the stay information acquirer, a background image generator which generates a background image from the captured image, and a display image generator which generates a display image by superimposing the heat map image generated by the heat map image generator on the background image generated by the background image generator, and wherein the background image generator generates the background image by performing image processing for reducing discriminability of the moving object appearing in the captured image on the captured image.