Depending on the lateral width thereof, an image recording material P is stably positioned on a recording drum, employing two positioning pins with an appropriate pitch therebetween. Non-contacting portions prevent any irrelevant positioning pins from coming into contact with the material P. The material P may be transported onto the recording drum 5 while one end thereof constitutes an angle U with a rotation axis 5N of the recording drum 5. A reference notch 44ae first fits with a positioning pin 51a. Thereafter, as the aforementioned end of the material P abuts with a positioning pin 51b, accurate positioning occurs. Each positioning pin 51 includes a tapered portion having a reference taper angle 2T. When a leading-end clamp 52 clamps the aforementioned end, the material P comes in contact with the tapered portion, with a, reduced friction force against the positioning pin 51, thereby preventing deformation of the material P.