To provide an image forming apparatus capable of maintaining an image forming accuracy to a recoding medium excellent by supporting the recording media positioned out of a platen in the image recording apparatus wherein a height of the platen can be displaced according to a thickness of recording media.

An inkjet printer 100 has a platen 101 for loading recording media WK. The platen 101 is displaceable with regard to a position along the height direction by a platen displacement mechanism 120. Both front and rear sides of the platen 101 are provided with supporting devices 130, 140 having supporting parts 131, 141 for supporting the recording media WK positioned out of the platen 101. The supporting parts 131, 141 are provided with engaging parts 134, 135, 144, 145 mounted on receiving parts 113, 114, 115, 116 disposed on the platen 101. Further, the supporting parts 131, 141 are supported on supporting pedestals 133, 143 through links 132, 142 so as to be able to ascend and descend.