The invention relates to an ablation apparatus for ablating a structure (14) within tissue of a living being. An ultrasound visualization unit (15) generates a two-dimensional or a three-dimensional ultrasound image for finding the structure to be ablated within the tissue. Ablation energy provided by an ablation unit (19) can then accurately be directed to the found structure. Moreover, the ultrasound visualization unit is adapted to generate during the provision of the ablation energy an M-mode ultrasound image by sending and receiving ultrasound waves in the direction, in which the structure is located, as found by using the two-dimensional or three-dimensional ultrasound image, thereby monitoring the ablation procedure. This allows for an improved control of the ablation procedure and, thus, for an improved quality of this procedure.