1. A camera position posture evaluating device comprising: at least one of a resolution evaluating unit which evaluates resolution of a target object in an image obtained by capturing the image of the target object arranged at each position in a target area, according to a resolution evaluation function which defines a relationship between the resolution and a first suitability rate which indicates suitability of image processing, and thereby derives the first suitability rate matching each position in the target area, and a gazing point angle evaluating unit which evaluates a gazing point angle which is an angle formed between a straight line which passes on a gazing point in the target object arranged at each position in the target area and a position of a camera, and a ground according to a gazing point angle evaluation function which defines a relationship between the gazing point angle and a second suitability rate which indicates suitability of the image processing, and thereby derives the second suitability rate matching each position in the target area; a target area evaluating unit which derives a third suitability rate which is determined based on to what degree a target object field-of-view area which is a collection of positions which are positions on the ground in real space which meet pixel positions in the image and in which the entirety of the target object fits in the image when the target object is arranged at the positions, and the target area accurately overlap, and which indicates the suitability of the image processing; and a comprehensive evaluating unit which, based on at least one of the first suitability rate matching each position in the target area and the second suitability rate matching each position in the target area, and the third suitability rate, derives an evaluation index which indicates to what degree a state of the camera is suitable to the image processing.