An image forming apparatus is provided which shortens the time for image formation, thereby improving the convenience. To achieve this, the control part of the image forming apparatus has a job data acquisition part and a conveyance speed control part. The job data acquisition part acquires job data from an operation panel part, a document reading part, an external terminal, or the like. The conveyance speed control part measures the temperature of a temperature sensor at the time of initial start-up operation of conveying a recording sheet, and at the time when the recording sheet has reached a registration roller pair, respectively. Further, the conveyance speed control part selects whether or not to wait for a prescribed waiting time and whether or not to reduce the fixing speed below a normal speed, according to a condition corresponding to the respective measured temperatures.