An agitator ball mill comprises agitating discs (18) on an agitating shaft, wherein two adjacent agitating discs (18) are bounding a grinding cell, respectively. The agitating discs (18) comprise grinding material passage openings (28) which are only arranged in the immediate proximity of a grinding chamber inner boundary (19), which connect adjacent grinding cells, and which have a radially outer boundary that has a distance R28 starting from the grinding chamber inner boundary (19) in the radial direction of the agitating disc (18). For the ratio of the distance R28 of the radially outer boundaries of the grinding material passage openings (28) to a radial extension R18 of the agitating discs (18), the following condition applies: 0.05·R18≤R28≤0.25·R18. Otherwise the agitating discs (18) are closed.