A stabilizer leg arrangement for supporting a mobile working machine against the ground, the stabilizer leg arrangement comprising: - a support beam to be fixedly connected to a base structure of the mobile working machine; - an extension arm mounted to the support beam, the extension arm being telescopically extensible in order to allow an adjustment of the horizontal extension length thereof, wherein the extension arm comprises an extension beam which is telescopically mounted to the support beam so as to be axially slidable in relation to the support beam in the longitudinal direction of the extension arm in order to vary the horizontal extension length thereof, and wherein this extension beam extends into an interior space of the support beam through an entrance opening provided at an end of the support beam; - a stabilizer leg mounted to the extension arm at an outer end thereof, the stabilizer leg being extensible in a vertical direction by means of an actuator, wherein a foot plate is arranged at a lower end of the stabilizer leg so as to be vertically moveable, by a vertical extension of the stabilizer leg under the effect of the actuator, from a raised position, in which the foot plate is lifted from the ground, to a lowered operating position, in which the foot plate is in supporting contact with the ground; and - a measuring system for establishing the magnitude of the support force acting on said foot plate in the operating position, characterized in that the measuring system comprises: - a length measuring device configured to generate a first measuring value that depends on the extension length of the extension arm; - a force sensor which is arranged on the support beam in the vicinity of the entrance opening and which is configured to generate a second measuring value that depends on the contact force between said extension beam and the support beam at the entrance opening; and - an electronic processing device configured to establish the magnitude of the support force based on said first and second measuring values. - a support beam to be fixedly connected to a base structure of the mobile working machine; - an extension arm mounted to the support beam, the extension arm being telescopically extensible in order to allow an adjustment of the horizontal extension length thereof, wherein the extension arm comprises an extension beam which is telescopically mounted to the support beam so as to be axially slidable in relation to the support beam in the longitudinal direction of the extension arm in order to vary the horizontal extension length thereof, and wherein this extension beam extends into an interior space of the support beam through an entrance opening provided at an end of the support beam; - a stabilizer leg mounted to the extension arm at an outer end thereof, the stabilizer leg being extensible in a vertical direction by means of an actuator, wherein a foot plate is arranged at a lower end of the stabilizer leg so as to be vertically moveable, by a vertical extension of the stabilizer leg under the effect of the actuator, from a raised position, in which the foot plate is lifted from the ground, to a lowered operating position, in which the foot plate is in supporting contact with the ground; and - a measuring system for establishing the magnitude of the support force acting on said foot plate in the operating position, - a length measuring device configured to generate a first measuring value that depends on the extension length of the extension arm; - a force sensor which is arranged on the support beam in the vicinity of the entrance opening and which is configured to generate a second measuring value that depends on the contact force between said extension beam and the support beam at the entrance opening; and - an electronic processing device configured to establish the magnitude of the support force based on said first and second measuring values.