Mammography imaging apparatus according to the invention contains e.g. an essentially vertically standing body part and an arm structure in connection with it, being turnable with respect to a horizontal rotating axis, a radiation source on one hand and image data receiving means on the other hand being located at essentially opposite ends of the arm structure. The arm structure includes at least two arm parts orientating essentially parallel and means for changing mutual orientation of at least the first and the second of the said at least two arm parts, first means for turning the said first arm part around a horizontal axis and second means arranged to the said second arm part with help of which, when turning the said first arm part, it is possible both to maintain orientation of the said second arm part with respect to the said first arm part and to turn the said second arm part in a different direction and/or at a different angular velocity with respect to the movement of the said first arm part.Mammography imaging apparatus according to the invention contains e.g. an essentially vertically standing body part and an arm structure in connection with it, being turnable in relation to a horizontal rotating axle, a radiation source on one hand and image data receiving means on the other hand being placed at essentially opposite ends of the arm structure. The arm structure includes at least two essentially parallel orientating arm parts and means for changing mutual orientation of at least first and second of the said at least two arm parts, first means for turning the said first arm part around a horizontal axle and second means arranged to the said second arm part with help of which, when turning the said first arm part it is possible both to maintain the orientation of the said second arm part in relation to the said first arm part and to turn the said second arm part in a different direction and/or with a different angular velocity in relation to the movement of
