A medical apparatus comprising: an endoscopic insertion portion provided with an image pickup means and a channel (2F1) which passes through an inner part; treatment means provided with a sensor and a bending portion and passed through the channel (2F1), with a distal end portion of the treatment means being allowed to protrude from an insertion-portion distal end portion of the endoscopic insertion portion, where the sensor is disposed in the distal end portion and configured to detect a position, a direction, and a roll angle and the bending portion is adapted to bend the distal end portion; storage means adapted to store three-dimensional image data of the lumen of a subject acquired in advance; target position setting means adapted to set the target position based on the three-dimensional image data; and virtual endoscopic image generating means adapted to generate a virtual endoscopic image by using a line-of-sight parameter which includes the position, the direction, and the roll angle of the distal end portion detected by the sensor, based on the three-dimensional image data, and wherein the bending portion is bendable either in an up/down direction or a left/right direction, characterized by image processing means adapted to perform a superimposition process and thereby display operation information used to insert the distal end portion to the target position in superimposition on the virtual endoscopic image, wherein the operation information processed by the image processing means is information about a bending angle of the bending portion and a roll angle of the distal end portion. an endoscopic insertion portion provided with an image pickup means and a channel (2F1) which passes through an inner part; treatment means provided with a sensor and a bending portion and passed through the channel (2F1), with a distal end portion of the treatment means being allowed to protrude from an insertion-portion distal end portion of the endoscopic insertion portion, where the sensor is disposed in the distal end portion and configured to detect a position, a direction, and a roll angle and the bending portion is adapted to bend the distal end portion; storage means adapted to store three-dimensional image data of the lumen of a subject acquired in advance; target position setting means adapted to set the target position based on the three-dimensional image data; and virtual endoscopic image generating means adapted to generate a virtual endoscopic image by using a line-of-sight parameter which includes the position, the direction, and the roll angle of the distal end portion detected by the sensor, based on the three-dimensional image data, and wherein the bending portion is bendable either in an up/down direction or a left/right direction, characterized by image processing means adapted to perform a superimposition process and thereby display operation information used to insert the distal end portion to the target position in superimposition on the virtual endoscopic image, wherein the operation information processed by the image processing means is information about a bending angle of the bending portion and a roll angle of the distal end portion.