A waste toner transporting device includes a waste toner passing passage, a waste toner collection container, a suction passage, a suction device, and a passing passage box. Through the waste toner passing passage, waste toner passes. The waste toner collection container collects the waste toner having passed through the waste toner passing passage. In the suction passage, suspended toner is sucked along with air inside a developing device. The suction device sucks the air inside the suction passage. Inside the passing passage box, the waste toner passing passage constituting part of the waste toner passing passage is formed. The suction passage constituting part of the suction passage is formed inside the passing passage box so as to be connected to the waste toner passing passage.