An apparatus is provided for measuring the weight force of a bale in a baler wherein the bale moves between a first position, within the baling chamber, and a second position, within a wrapping apparatus carried by the baler chassis. A measurement device, which is connected to a data processing device, is provided, for measuring a measurement parameter influenced by the weight force of said bale in each of said first and second positions and developing a signal representative of the weight of the bale at those positions. The processing device is set up to calculate the weight force of the bale taking into account a first signal output from the measurement device when the bale is in the first position and a second signal output from the measurement device when the bale is in the second position.