A medical system having a first insertable instrument having a first image sensor； a second insertable instrument having a second image sensor； a first arm configured to move the first insertable instrument； and a controller configured to: acquire a position and orientation of the second insertable instrument in a predetermined coordinate system； calculate a position and direction of an optical axis of the second image sensor based on the position and orientation of the second insertable instrument； acquire a position and orientation of the first insertable instrument in the predetermined coordinate system； calculate a first operation amount of the first arm to move the first image sensor such that the optical axis of the second image sensor substantially coincides with an optical axis of the first image sensor, based on the position and orientation of the first insertable instrument； and control the first arm based on the first operation amount.
