The impact shield (9, 10) carries a plurality of armor bodies (16) of a strongly wear resisting material. The armor bodies (16) are fixed horizontally in succession on a front side of the impact shield by a fixing element making it possible to detach them from the impact shield (9, 10) for their replacement. The impact shield (9, 10) is composed of a fixed part (21) connected to the frame (2), and a removable part (22) carrying the armor bodies (16) and making it possible to remove simultaneously all the armor bodies, fixed on the same, out of the grinding chamber (3). At least one such impact shield (9, 10) is arranged in a grinding chamber (3) of an impact grinding mill including a frame (2) further including a horizontal-axis rotor (6) provided with impactors (7) arranged regularly around its periphery.