A display image formation apparatus for surveillance comprising: a designation section that receives a user's designation of a position on a plan map, a camera selection section that selects one omni-directional camera from among a plurality of omni-directional cameras based on each distance between the designated position and positions of the plurality of omni-directional cameras, wherein the distance of the selected camera is the smallest distance; an extraction region determining section that determines an extracted image region, a portion of which corresponds to the designated position, to be extracted from the omni-directional image captured by the selected one omni-directional camera selected by the camera selection section; and a drawing section that forms a display image which includes the extracted image region, as an image of the designated position, overlapping the plan map, wherein the designation section further receives a drag input which indicates successive update of the designated position, and wherein either - the camera selection section does not change the selected one omni-directional camera, regardless of a positional relationship between the updated designated position and the positions of the plurality of omni-directional cameras, while the designation section is receiving the drag input, or - the extracted region determining section determines the extracted image region such that an angle of view of the image region is gradually changed from an original angle of view (Zn) to a wide-angle (Zw) from a position at a predetermined distance from a camera switching point and such that after passing through the camera switching point, the angle of view is gradually returned to original angle of view (Zn) to a position at a predetermined distance. a designation section that receives a user's designation of a position on a plan map, a camera selection section that selects one omni-directional camera from among a plurality of omni-directional cameras based on each distance between the designated position and positions of the plurality of omni-directional cameras, wherein the distance of the selected camera is the smallest distance; an extraction region determining section that determines an extracted image region, a portion of which corresponds to the designated position, to be extracted from the omni-directional image captured by the selected one omni-directional camera selected by the camera selection section; and a drawing section that forms a display image which includes the extracted image region, as an image of the designated position, overlapping the plan map, wherein the designation section further receives a drag input which indicates successive update of the designated position, and wherein either - the camera selection section does not change the selected one omni-directional camera, regardless of a positional relationship between the updated designated position and the positions of the plurality of omni-directional cameras, while the designation section is receiving the drag input, or - the extracted region determining section determines the extracted image region such that an angle of view of the image region is gradually changed from an original angle of view (Zn) to a wide-angle (Zw) from a position at a predetermined distance from a camera switching point and such that after passing through the camera switching point, the angle of view is gradually returned to original angle of view (Zn) to a position at a predetermined distance. - the camera selection section does not change the selected one omni-directional camera, regardless of a positional relationship between the updated designated position and the positions of the plurality of omni-directional cameras, while the designation section is receiving the drag input, or - the extracted region determining section determines the extracted image region such that an angle of view of the image region is gradually changed from an original angle of view (Zn) to a wide-angle (Zw) from a position at a predetermined distance from a camera switching point and such that after passing through the camera switching point, the angle of view is gradually returned to original angle of view (Zn) to a position at a predetermined distance.