A rotary tool (101; 201), comprising: a tool body (103; 203), a drive shaft (112; 212) disposed in the tool body (103; 203), a driven shaft (121; 221) to which a tool bit (125; 225) is attached, an Oldham's coupling (123; 223) that is disposed between the drive shaft (112; 212) and the driven shaft (121; 221) and transmits rotation of the drive shaft (112; 212) to the driven shaft (121; 221), and an elastic element (141; 241) that is disposed between the driven shaft (121; 221) and the tool body (103; 203), wherein: the driven shaft (121; 221) is prevented from moving in a longitudinal direction of the driven shaft (121; 221) relative to the tool body (103; 203) and allowed to move in a direction transverse to the longitudinal direction of the driven shaft (121; 221) relative to the tool body (103; 203), and during said relative movement, power transmission from the drive shaft (112; 212) to the driven shaft (121; 221) is maintained via the Oldham's coupling (123; 223), and the elastic element (141; 241) absorbs the movement of the driven shaft (121; 221) relative to the tool body (103; 203) in the direction transverse to the longitudinal direction of the driven shaft, characterized in that the rotary tool further comprises a cover (133; 233) disposed around the driven shaft (121; 221), wherein the elastic element (141; 241) is disposed in a circumferential direction between an outer surface of the cover (133; 233) and an inner surface of the tool body (103; 203). a tool body (103; 203), a drive shaft (112; 212) disposed in the tool body (103; 203), a driven shaft (121; 221) to which a tool bit (125; 225) is attached, an Oldham's coupling (123; 223) that is disposed between the drive shaft (112; 212) and the driven shaft (121; 221) and transmits rotation of the drive shaft (112; 212) to the driven shaft (121; 221), and an elastic element (141; 241) that is disposed between the driven shaft (121; 221) and the tool body (103; 203), wherein: the driven shaft (121; 221) is prevented from moving in a longitudinal direction of the driven shaft (121; 221) relative to the tool body (103; 203) and allowed to move in a direction transverse to the longitudinal direction of the driven shaft (121; 221) relative to the tool body (103; 203), and during said relative movement, power transmission from the drive shaft (112; 212) to the driven shaft (121; 221) is maintained via the Oldham's coupling (123; 223), and the elastic element (141; 241) absorbs the movement of the driven shaft (121; 221) relative to the tool body (103; 203) in the direction transverse to the longitudinal direction of the driven shaft, characterized in that the rotary tool further comprises a cover (133; 233) disposed around the driven shaft (121; 221), wherein the elastic element (141; 241) is disposed in a circumferential direction between an outer surface of the cover (133; 233) and an inner surface of the tool body (103; 203). the driven shaft (121; 221) is prevented from moving in a longitudinal direction of the driven shaft (121; 221) relative to the tool body (103; 203) and allowed to move in a direction transverse to the longitudinal direction of the driven shaft (121; 221) relative to the tool body (103; 203), and during said relative movement, power transmission from the drive shaft (112; 212) to the driven shaft (121; 221) is maintained via the Oldham's coupling (123; 223), and the elastic element (141; 241) absorbs the movement of the driven shaft (121; 221) relative to the tool body (103; 203) in the direction transverse to the longitudinal direction of the driven shaft, characterized in that the rotary tool further comprises a cover (133; 233) disposed around the driven shaft (121; 221), wherein the elastic element (141; 241) is disposed in a circumferential direction between an outer surface of the cover (133; 233) and an inner surface of the tool body (103; 203).