NOVELTY - The device (D) has a lower wall (PI) provided at a lower face with a housing (R) to place a lower part of an edge (BO) of an opening (OS) defined at a side wall (PL1) of a battery support (SB). A front part is arranged to support a part on a heel plate (TB) of a battery type equipment (BA). An upper wall (PS) is coupled with the lower wall and provided on an upper face of a fixation lug (PF) so as to connect with the side wall of the support to retain an upper part of the device with respect to the side wall for allowing immobilization of the equipment with respect to the support.    USE - Immobilization device for use with an accessory support to support an electronic computer, case of fuses e.g. Case of Protection and Management of a Food (BPGA) or Case of Constraint Departure Battery (BSBD), and air filter, utilized for immobilization of a battery type equipment in a motor vehicle (all claimed) i.e. car, with respect to a battery support.    ADVANTAGE - The device is solidarized with the side wall of the battery support, where a higher face of the battery is entirely released for fixing of an element e.g. case of fuses, so as to facilitate work of a technician. The upper wall is coupled with the lower wall and provided on the upper face of the fixation lug that is arranged so as to connect with the side wall of the support to retain the upper part of the device with respect to the side wall, thus allowing immobilization of the equipment with respect to the support and reducing forgery.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for an accessory support comprising a side wall that is provided outside an immobilization device.    DESCRIPTION OF DRAWING(S) - The drawing shows a transverse cross-sectional view of an immobilization device that is solidarized with an accessory support to immobilize a battery with respect to a battery support.    Battery type equipment (BA)    Edge of opening (BO)    Immobilization device (D)    Opening (OS)    Fixation lug (PF)    Lower wall of immobilization device (PI)    Side wall of battery support (PL1)    Upper wall of immobilization device (PS)    Housing (R)    Battery support (SB)    Heel plate (TB)