To provide, in a head part of a device in which the head part is composed of two head devices, a head mechanism that can form a space when needed around the head devices that are closely arranged mutually while being miniaturized in the width direction.

In the head mechanism of the head part composed of two head devices that are arranged in a carriage that is slidably arranged along a guide rail, at least one head device is rotatably arranged in the carriage, and the head device rotatably arranged in the carriage is detachably arranged in an attaching/detaching mechanism.