An image forming apparatus includes: a transfer portion for transferring an image onto a sheet at a transfer nip; a fixing portion for fixing the image on the sheet at a fixing nip; a sheet feeding guide, provided between the transfer portion and the fixing portion, having a sheet guide surface; a sheet detecting portion provided between the transfer portion and the fixing portion; and a controller for controlling a sheet feeding speed of at least one of the transfer portion and the fixing portion depending on an output of the sheet detecting portion so that a feeding attitude of the sheet sandwiched at both of the transfer nip and the fixing nip is maintained in a predetermined feeding attitude. The sheet guide surface of the sheet feeding guide has a most recessed region in a region between the transfer portion and the sheet detecting portion.