CONVEYANCE GUIDE UNIT

The conveyance guide unit is provided with a guide member, a supporting frame, and an external cover. The guide member guides a sheet, which is discharged from a sheet discharge port of the image forming apparatus or from a sheet discharge port of a relay conveyance device installed in the image forming apparatus, to the sheet carrying-in port of a post-processing device. The supporting frame supports the guide member. The external cover is fixed to the supporting frame; the external cover covers an upper part of the guide member and side parts of the guide member in a traverse direction of a sheet conveyance path, which is perpendicular to a sheet conveyance direction. The external cover has an upper surface serving as an extension part of a discharge tray part of the post-processing device, the extension part being extended downstream, in a sheet discharge direction.