PROBLEM TO BE SOLVED: To simplify paracentesis and improve its certainty.SOLUTION: A paracentesis planning section 33 sets an ablation planned area on a medical image following an instruction from a user. The paracentesis planning section 33 determines various planned puncture routes for paracentesis needles which are use candidates for ablation to be executed on the basis of at least one geometric feature among position, shape and size of the ablation planned area. A display control section 35 displays the planned puncture routes superimposing them on the medical image.