Attachment structure for engine accessory

In order to easily provide a belt-driven engine accessory having a structure that is smoothly attached to the proper position on an engine body, a compressor (100) driven via a belt (3) is fastened by: inserting three bolts (8) respectively into a first bolt insertion hole (5) having a perfectly circular cross-section with the smallest mating gap, a second bolt insertion hole (6) having an elliptical cross-section in the hole portion near an accessory attachment part (9) and having a perfectly circular shape with a diameter equal to or greater than the major axis of the elliptical shape in the hole portion leading up to the head of the bolt, and a third bolt insertion hole (7) having a perfectly circular cross-section of sufficiently large diameter; and threading the bolts (8) into corresponding screw holes (10) of the accessory attachment part (9). 为了简单地提供种将由皮带驱动的发动机辅助设备顺利地安装在发动机主体侧的正确位置处的结构，使分别插通到第螺栓插通孔(5)、第二螺栓插通孔(6)、第三螺栓插通孔(7)中的三根螺栓(8)与辅助设备安装部(9)的对应的螺纹孔(10)螺合，来将经由皮带(3)而被驱动的压缩机(100)紧固连接，其中，所述第螺栓插通孔(5)呈具有最小嵌