Device for securing a load, such as a cargo item, under an aircraft, in particular under a fighter aircraft wing or under a combat helicopter airframe, comprising: - a first upper ball joint which is for connection to a fixed structure of the aircraft and which comprises in particular securing rollers which can be moved radially and which are arranged in an axially movable tubular member, - a second lower connection ball joint which is connected to a movable structure such as a cargo item, the second ball joint being able to be connected to the first ball joint by means of the securing rollers when they are in a position spaced apart radially in the second ball joint in order to form therewith a male/female type connection, - a piston which is capable, on the one hand, of blocking the radially spaced-apart rollers in the second ball joint when the securing device is in a retracted locking position and, on the other hand, of unblocking the rollers so as to unlock the securing device, - a preloading generation system which is intended to maintain, over a long time, the connection between the two ball joints in the retracted locking position of the securing device, characterised in that the preloading generation system comprises: - a hydraulic preloading chamber which is arranged around the movable tubular member and which is connected to the fixed structure by means of the first upper ball joint, the movable member sliding axially in the hydraulic chamber and - an electromechanical actuator which is connected to the movable tubular member, the electromechanical actuator being capable, on the one hand, of axially blocking the tubular member in a retracted locking position of the securing device so as to maintain the preloading generated by the hydraulic pressure in the hydraulic chamber once the pressure is withdrawn and, on the other hand, of axially pushing the piston in order to radially unblock the rollers so as to unlock the securing device. - a first upper ball joint which is for connection to a fixed structure of the aircraft and which comprises in particular securing rollers which can be moved radially and which are arranged in an axially movable tubular member, - a second lower connection ball joint which is connected to a movable structure such as a cargo item, the second ball joint being able to be connected to the first ball joint by means of the securing rollers when they are in a position spaced apart radially in the second ball joint in order to form therewith a male/female type connection, - a piston which is capable, on the one hand, of blocking the radially spaced-apart rollers in the second ball joint when the securing device is in a retracted locking position and, on the other hand, of unblocking the rollers so as to unlock the securing device, - a preloading generation system which is intended to maintain, over a long time, the connection between the two ball joints in the retracted locking position of the securing device, - a hydraulic preloading chamber which is arranged around the movable tubular member and which is connected to the fixed structure by means of the first upper ball joint, the movable member sliding axially in the hydraulic chamber and - an electromechanical actuator which is connected to the movable tubular member, the electromechanical actuator being capable, on the one hand, of axially blocking the tubular member in a retracted locking position of the securing device so as to maintain the preloading generated by the hydraulic pressure in the hydraulic chamber once the pressure is withdrawn and, on the other hand, of axially pushing the piston in order to radially unblock the rollers so as to unlock the securing device.