A stabilizer leg device with a stabilizer leg to be moved downwards from an object, such as a crane vehicle, so as to stabilize this object by bearing through a footplate secured to a lower end of the stabilizer leg onto a support layer on which the object is resting, said device comprising • a holder configured to be fixed with respect to said object and to receive and hold a first member of the stabilizer leg vertically displaceable with respect to the holder, • a first power member configured to act between said object and said first stabilizer leg member below the holder by varying its length so as to displace said first stabilizer leg member vertically upwards and downwards with respect to the holder, characterised in that a second power member belonging to the stabilizer leg and configured to change the distance between an upper end of the first stabilizer leg member and said footplate by varying its length and by that extend or retract a second stabilizer leg member provided with the footplate with respect to said first stabilizer leg member, and • a locking arrangement configured, in a working position of the stabilizer leg device with the first stabilizer leg member in a lower end position, to lock the first stabilizer leg member with respect to the holder against vertical movements with respect thereto, wherein the locking arrangement comprises a first locking member on the first stabilizer leg member and a second locking member on the holder, that the device further comprises a control arrangement configured to transfer the locking arrangement into a locking state by causing mutual engagement of said locking members and into an unlocked state by releasing the engagement of the locking members, and that the control arrangement comprises a member (15, 16, 15', 16') interconnecting the locking arrangement and said second stabilizer leg member to make the state of the locking arrangement dependent upon the vertical distance of the footplate to the first stabilizer leg member by automatically transferring the locking arrangement into said locking state upon displacing the footplate downwards towards a working position of the stabilizer leg device and reaching a determined extension degree of the second stabilizer leg member and upon retracting the second stabilizer leg member from a working position of the stabilizer leg device upon passing said determined extension degree automatically transfer the locking arrangement into an unlocked state enabling upwards movement of the first stabilizer leg member with respect to the holder. • a holder configured to be fixed with respect to said object and to receive and hold a first member of the stabilizer leg vertically displaceable with respect to the holder, • a first power member configured to act between said object and said first stabilizer leg member below the holder by varying its length so as to displace said first stabilizer leg member vertically upwards and downwards with respect to the holder, characterised in that a second power member belonging to the stabilizer leg and configured to change the distance between an upper end of the first stabilizer leg member and said footplate by varying its length and by that extend or retract a second stabilizer leg member provided with the footplate with respect to said first stabilizer leg member, and • a locking arrangement configured, in a working position of the stabilizer leg device with the first stabilizer leg member in a lower end position, to lock the first stabilizer leg member with respect to the holder against vertical movements with respect thereto,