A protector comprising: a protector main body including a base, paired opposed wall portions (12a, 12b) protruding from the base and opposed to each other along an opposed direction, a routing space that is formed by the base and the paired opposed wall portions (12a, 12b) and through which a wire is routed, and an opening that is formed by end portions (12e, 12f) of the paired opposed wall portions (12a, 12b) on an opposite side from the base and that opens on one side in a protruding direction of the opposed wall portions (12a, 12b) with respect to the base; a lid member that closes the opening; a locking mechanism including a locking hole that is formed in the lid member and opens on opposite sides in the protruding direction and a locking lug portion that is positioned at the end portion of the opposed wall portion on a side of the opening and that is inserted to and locked to the locking hole, the locking mechanism locking the protector main body and the lid member to each other in a correct position where the lid member closes the opening; and paired guide mechanisms (40A, 40B) including paired guide chips (41A, 41B) respectively positioned at opposite end portions in the opposed direction of the lid member and extending along the protruding direction and paired guide holes (42A, 42B) that are respectively positioned at the end portions (12e, 12f) of the paired opposed wall portions (12a, 12b) on the side of the opening and into which the paired guide chips (41A, 41B) are respectively inserted along the protruding direction, wherein protruding amounts (L1, L2) along the protruding direction of the paired guide chips (41A, 41B) are set such that the guide chips (41A, 41B) are inserted into the guide holes (42A, 42B) before the locking lug portion is locked to the locking hole, and each of the paired guide holes (42A, 42B) is adjacent to the locking hole in an adjacent direction intersecting the protruding direction and the opposed direction when the lid member is disposed in the correct position for closing the opening. a protector main body including a base, paired opposed wall portions (12a, 12b) protruding from the base and opposed to each other along an opposed direction, a routing space that is formed by the base and the paired opposed wall portions (12a, 12b) and through which a wire is routed, and an opening that is formed by end portions (12e, 12f) of the paired opposed wall portions (12a, 12b) on an opposite side from the base and that opens on one side in a protruding direction of the opposed wall portions (12a, 12b) with respect to the base; a lid member that closes the opening; a locking mechanism including a locking hole that is formed in the lid member and opens on opposite sides in the protruding direction and a locking lug portion that is positioned at the end portion of the opposed wall portion on a side of the opening and that is inserted to and locked to the locking hole, the locking mechanism locking the protector main body and the lid member to each other in a correct position where the lid member closes the opening; and paired guide mechanisms (40A, 40B) including paired guide chips (41A, 41B) respectively positioned at opposite end portions in the opposed direction of the lid member and extending along the protruding direction and paired guide holes (42A, 42B) that are respectively positioned at the end portions (12e, 12f) of the paired opposed wall portions (12a, 12b) on the side of the opening and into which the paired guide chips (41A, 41B) are respectively inserted along the protruding direction, wherein protruding amounts (L1, L2) along the protruding direction of the paired guide chips (41A, 41B) are set such that the guide chips (41A, 41B) are inserted into the guide holes (42A, 42B) before the locking lug portion is locked to the locking hole, and each of the paired guide holes (42A, 42B) is adjacent to the locking hole in an adjacent direction intersecting the protruding direction and the opposed direction when the lid member is disposed in the correct position for closing the opening.