To provide a medical energy irradiation apparatus which permits easy and accurate establishment of a site of tissues of a living body targeted for irradiation with energy, when doctors use the medical energy irradiation apparatus to perform a cure for a prostatic hyperplasia or the like. The doctors insert an applicator 110 of the medical energy irradiation apparatus to an urinary bladder 161 and fix an endoscope 135 near to an entrance of an urethra. In this arrangement, when observing with the endoscope (135), a seminal colliculas 144 observed through a side-observation window 130 is observed toward a lower part of an observed image (schematic diagram) displayed on a display unit, and a positioning marker 140 in an interior of the applicator is observed toward an upper part of an observed image. The doctors can accurately determine a position to be irradiated with laser light from positions of the seminal colliculas 144 and the positioning marker 140 observed, and a direction of irradiation with laser light from a position of a direction marker 142, respectively.