A liquid discharge apparatus comprising: a liquid discharge unit having a liquid discharge port from which a liquid is discharged toward an object, the liquid discharge unit being movable along at least one of a first axis and a second axis intersecting the first axis and movable along a third axis intersecting the first axis and the second axis, the third axis being parallel to a direction in which the liquid is discharged from the liquid discharge port toward the object; and a contact detection unit detachably attached to the liquid discharge unit, wherein the contact detection unit includes: a first component configured to be detachably attached to the liquid discharge unit; and a second component configured to be detachably attached to the first component, and wherein the contact detection unit is configured to perform at least one of a position detection and a collision object detection in response to movement of the first component and the second component, wherein the contact detection unit includes: a position detector configured to detect a position of the object when the object is at the position of the liquid discharge unit along the first axis and the second axis as the second component moves relative to the first component along the third axis; and a collision object detector configured to detect a collision object on the object to collide with the liquid discharge unit as the second component moves relative to the first component along at least one of the first axis and the second axis, wherein the position detector and the collision object detector are configured to form a series connection circuit which is an electrically non-conductive state when the second component moves along any of the first, second and third axis, and wherein the contact detection unit is configured to output a signal indicating that the series connection circuit is in an electrically conductive state, when the second component does not move along any of the first axis, the second axis, and the third axis, the contact detection unit includes a position detector configured to detect a position of the object along the third axis relative to the liquid discharge unit. a liquid discharge unit having a liquid discharge port from which a liquid is discharged toward an object, the liquid discharge unit being movable along at least one of a first axis and a second axis intersecting the first axis and movable along a third axis intersecting the first axis and the second axis, the third axis being parallel to a direction in which the liquid is discharged from the liquid discharge port toward the object; and a contact detection unit detachably attached to the liquid discharge unit, wherein the contact detection unit includes: a first component configured to be detachably attached to the liquid discharge unit; and a second component configured to be detachably attached to the first component, and a first component configured to be detachably attached to the liquid discharge unit; and a second component configured to be detachably attached to the first component, and wherein the contact detection unit is configured to perform at least one of a position detection and a collision object detection in response to movement of the first component and the second component, wherein the contact detection unit includes: a position detector configured to detect a position of the object when the object is at the position of the liquid discharge unit along the first axis and the second axis as the second component moves relative to the first component along the third axis; and a collision object detector configured to detect a collision object on the object to collide with the liquid discharge unit as the second component moves relative to the first component along at least one of the first axis and the second axis, a position detector configured to detect a position of the object when the object is at the position of the liquid discharge unit along the first axis and the second axis as the second component moves relative to the first component along the third axis; and a collision object detector configured to detect a collision object on the object to collide with the liquid discharge unit as the second component moves relative to the first component along at least one of the first axis and the second axis, wherein the position detector and the collision object detector are configured to form a series connection circuit which is an electrically non-conductive state when the second component moves along any of the first, second and third axis, and wherein the contact detection unit is configured to output a signal indicating that the series connection circuit is in an electrically conductive state, when the second component does not move along any of the first axis, the second axis, and the third axis, the contact detection unit includes a position detector configured to detect a position of the object along the third axis relative to the liquid discharge unit.