According to an embodiment, a medical treatment apparatus includes: a first acquirer to acquire a group including five or more pairs of corresponding points on a first perspective image of a subject captured at a first timing and a second perspective image of the subject captured at a second timing a second acquirer to acquire a first parameter including position/orientation information of an imaging device capturing the first perspective image and conversion information related to a coordinate system of the first perspective image, and acquire a second parameter including position/orientation information of an imaging device capturing the second perspective image and conversion information related to a coordinate system of the second perspective image a calculator to calculate difference in position of the subject between the first timing and the second timing using the group and the parameters and a controller to control a subject position using the difference.
