The problem to be overcome by the present disclosure is to provide an impact rotary tool attachment and tool system, both of which are designed to allow the user to have various types of machining work done more easily. An impact rotary tool attachment (7; 7a; 7b; 7c) according to the present disclosure includes an input shaft (71), a second output shaft (73), and a driving force conversion mechanism (9; 9a; 9b). To the input shaft (71), rotational driving force is transmitted from a first output shaft (450) of an impact rotary tool (1). To the second output shaft (73), the rotational driving force is transmitted from the input shaft (71). The driving force conversion mechanism (9; 9a; 9b) performs, when the rotational driving force is transmitted from the input shaft (71) to the second output shaft (73), at least one of: translating a rotational axis of rotation produced by the rotational driving force; changing an angle defined by the rotational axis; and converting the rotational driving force into thrust driving force applied along the rotational axis.