In an obliquely traveling sheet correcting device with a simple arrangement capable of reducing the cost and size thereof and enhancing an obliquely traveling sheet correcting accuracy. Stopping members 15 are turnably disposed to the rotary shaft 18 of free conveyer rollers 13 constituting a pair of conveyer roller 13, 14, the leading edge of a sheet S conveyed by a pair of conveyer rollers 5 is stopped by being abutted against the collision surfaces 20a of the stopping members 15, the stopping members 15 are turned and retracted when the sheet forms a predetermined loop to permit the sheet S to pass therethrough. There is also provided an image forming apparatus provided with the obliquely traveling sheet correcting device.