An image forming apparatus comprising: a first conveyance path; an image forming means configured to form an image on a sheet passing through the first conveyance path; a first conveyance member configured to receive the sheet from the first conveyance path and convey the sheet to reverse the sheet; a second conveyance path through which the sheet reversed by the first conveyance member is guided to the first conveyance path; a first driving source configured to drive the first conveyance member; and the image forming apparatus being characterised in that it further comprises a controller configured to control the first driving source such that in a case where images are to be formed on a first surface of a preceding sheet, on a first surface of a succeeding sheet fed to the first conveyance path succeeding to the preceding sheet and on a second surface of the preceding sheet, the controller causes the first conveyance member to stop without reversing the preceding sheet (2B in FIG. 10A) in a direction of heading to the second conveyance path in a case where the image has been formed on the first surface of the preceding sheet and permission of preparing the image to be formed on the first surface of the succeeding sheet is not issued yet, and the controller causes the first conveyance member to restart conveyance of the preceding sheet (2B in FIG. 10C) to the second conveyance path based on timing when the image forming means starts preparing the image to be formed on the first surface of the succeeding sheet. a first conveyance path; an image forming means configured to form an image on a sheet passing through the first conveyance path; a first conveyance member configured to receive the sheet from the first conveyance path and convey the sheet to reverse the sheet; a second conveyance path through which the sheet reversed by the first conveyance member is guided to the first conveyance path; a first driving source configured to drive the first conveyance member; and the image forming apparatus being characterised in that it further comprises a controller configured to control the first driving source such that in a case where images are to be formed on a first surface of a preceding sheet, on a first surface of a succeeding sheet fed to the first conveyance path succeeding to the preceding sheet and on a second surface of the preceding sheet, the controller causes the first conveyance member to stop without reversing the preceding sheet (2B in FIG. 10A) in a direction of heading to the second conveyance path in a case where the image has been formed on the first surface of the preceding sheet and permission of preparing the image to be formed on the first surface of the succeeding sheet is not issued yet, and the controller causes the first conveyance member to restart conveyance of the preceding sheet (2B in FIG. 10C) to the second conveyance path based on timing when the image forming means starts preparing the image to be formed on the first surface of the succeeding sheet. in a case where images are to be formed on a first surface of a preceding sheet, on a first surface of a succeeding sheet fed to the first conveyance path succeeding to the preceding sheet and on a second surface of the preceding sheet, the controller causes the first conveyance member to stop without reversing the preceding sheet (2B in FIG. 10A) in a direction of heading to the second conveyance path in a case where the image has been formed on the first surface of the preceding sheet and permission of preparing the image to be formed on the first surface of the succeeding sheet is not issued yet, and the controller causes the first conveyance member to restart conveyance of the preceding sheet (2B in FIG. 10C) to the second conveyance path based on timing when the image forming means starts preparing the image to be formed on the first surface of the succeeding sheet.