An exercising device for strengthening of abdominal muscles with a frame having a resistance mechanism, the device including an inclined bench (3) associated with the press arm (4) connected to the resistance mechanism (9) creating resistance force only in one direction, whereas the press arm (4) is pivotally mounted at one end and its other end is positioned above the inclined bench (3), and is provided with means (8) for pushing and/or holding by user's hands.