A closure, for a bottle, with evidence of first opening suitable for being installed on the mouth of a bottle, the neck of which extends along a longitudinal direction X-X', wherein said closure shows two different closure positions, a first position before the first opening and a second position after the first opening at least visually evidencing said first opening, and where the closure comprises: - a pourer: ∘ extending towards the lower portion, i.e., towards where the bottle is located according to the longitudinal direction X-X', by means of a lower cylindrical skirt (1.2), intended for being located in an operative position coaxial with the neck of the bottle, and where this skirt (1.2) has fixing means (1.2.1) for fixing with the neck of the bottle, and ∘ comprising a threaded section (1.1); - a cap: ∘ having a threaded inner section (2.1) with a thread complementary to that of the threaded section (1.1) of the pourer such that screwing and unscrewing said cap gives rise to a rotation about the longitudinal direction X-X' and to an axial movement also along the same longitudinal direction X-X', characterised in that - the closure additionally comprises a locking part that can be moved axially with respect to the cap, according to the longitudinal direction X-X', the locking part having a retaining section (3.2) temporarily immobilizing said locking part with the pourer, such that the locking part is integral with the pourer until a large enough force separates them; and, - the inner surface of the cap has a wedge (2.7) such that the axial movement of the locking part relative to the cap according to the longitudinal direction X-X' during first opening allows the locking part to overcome the wedge (2.7), but, after overcoming the wedge (2.7), the locking part is prevented by the wedge (2.7) from passing in the opposite direction and from returning to its initial position with respect to the cap, such that after the first opening the act of closing of the cap by screwing onto the pourer occurs with a mutual separation between the cap and the pourer that is greater than that established before the first opening. - a pourer: ∘ extending towards the lower portion, i.e., towards where the bottle is located according to the longitudinal direction X-X', by means of a lower cylindrical skirt (1.2), intended for being located in an operative position coaxial with the neck of the bottle, and where this skirt (1.2) has fixing means (1.2.1) for fixing with the neck of the bottle, and ∘ comprising a threaded section (1.1); ∘ extending towards the lower portion, i.e., towards where the bottle is located according to the longitudinal direction X-X', by means of a lower cylindrical skirt (1.2), intended for being located in an operative position coaxial with the neck of the bottle, and where this skirt (1.2) has fixing means (1.2.1) for fixing with the neck of the bottle, and ∘ comprising a threaded section (1.1); - a cap: ∘ having a threaded inner section (2.1) with a thread complementary to that of the threaded section (1.1) of the pourer such that screwing and unscrewing said cap gives rise to a rotation about the longitudinal direction X-X' and to an axial movement also along the same longitudinal direction X-X', characterised in that ∘ having a threaded inner section (2.1) with a thread complementary to that of the threaded section (1.1) of the pourer such that screwing and unscrewing said cap gives rise to a rotation about the longitudinal direction X-X' and to an axial movement also along the same longitudinal direction X-X', characterised in that - the closure additionally comprises a locking part that can be moved axially with respect to the cap, according to the longitudinal direction X-X', the locking part having a retaining section (3.2) temporarily immobilizing said locking part with the pourer, such that the locking part is integral with the pourer until a large enough force separates them; and, - the inner surface of the cap has a wedge (2.7) such that the axial movement of the locking part relative to the cap according to the longitudinal direction X-X' during first opening allows the locking part to overcome the wedge (2.7), but, after overcoming the wedge (2.7), the locking part is prevented by the wedge (2.7) from passing in the opposite direction and from returning to its initial position with respect to the cap, such that after the first opening the act of closing of the cap by screwing onto the pourer occurs with a mutual separation between the cap and the pourer that is greater than that established before the first opening.