To provide a structure for detection of a register mark which makes it possible rapid positioning of a register mark detector and reduces the number of media to be printed insufficiently.

At least one mark for determining position is arranged in front of a register mark 17 seeing from a moving direction in order to measure a position error of a receiver which scanns the register mark relative to a track 16 positioned in the moving direction of the register mark. An mark for determining position 21 has at least one side 29 positioned sideways relative to the track 16. A length B of the mark for determining position is several times as much as a length of the register mark 17. The mark for determining position has a predetermined positioning relation with the track 16.