To execute correct positioning for a head holder and a slide base by providing a positioning section that prevents the head holder from moving in the direction perpendicular to a reference plane and in the direction intercepting the perpendicular direction, respectively.

This carriage unit is provided with a slide base 40 that moved forward and backward freely in the directions of arrows B, B' and ahead holder 60 that is fixed to the slide base 40. A plate spring 58 that presses the head holder 60 in the direction of the arrow B is fixed to the side of the slide base 40. The second colliding portion 74 projecting in the direction of the arrow B' is formed on the side of the first colliding portion 68 of the head holder 60. The second colliding section 74 is attracted to the side 48 of the slide base 40 by the plate spring 58, but both collide with each other and are prohibited from moving in the directions of the arrows B, B', and their stop positions are determined. Thus, the second collision portion 74, the 5th colliding portion (side 48) and the plate spring 58 bring the head holder 60 to a halt.