A lens cap comprising: a cap main frame that covers a front end opening of a lens barrel; and a pair of operating members (3A, 3B) attached to a front surface of the cap main frame in such a manner as to allow the operating members (3A, 3B) to slide inward and outward with respect to the center of the cap main frame, wherein, when the operating members (3A, 3B) are made to slide outward by a biasing force, engaging portions at outer ends of the operating members (3A, 3B) are engaged with to-be-engaged portions in the front end opening, and the cap main frame is attached to the front end opening of the lens barrel, first locking portions are formed at inner edges of the operating members (3A, 3B), and second locking portions are formed on back surfaces of the operating members (3A, 3B), characterised in that: the lens cap further comprises: concave portions formed on the front surface of the cap main frame, the concave portions surrounding outer peripheral surfaces of the operating members (3A, 3B) so as to prevent the operating members (3A, 3B) from protruding outward from an outer peripheral surface of the cap main frame, first openings and second openings are formed in bottoms of the concave portions, the engaging portions of the operating members (3A, 3B) being engaged with a side of the back surface from the front surface through the first openings, the first locking portions of the operating members (3A, 3B) being locked with the side of the back surface from the front surface through the second openings, cover plates (5A, 5B) are placed on the back surface of the cap main frame, the cover plates (5A, 5B) having first to-be-locked portions and second to-be-locked portions, the first to-be-locked portions being locked with the first locking portions of the operating members (3A, 3B), the second to-be-locked portions being locked with the second locking portions of the operating members (3A, 3B), and biasing members are placed between the cover plates (5A, 5B) and the back surface of the cap main frame, the operating members (3A, 3B) being made to slide outward when the cover plates (5A, 5B) are pushed outward by the biasing members. a cap main frame that covers a front end opening of a lens barrel; and a pair of operating members (3A, 3B) attached to a front surface of the cap main frame in such a manner as to allow the operating members (3A, 3B) to slide inward and outward with respect to the center of the cap main frame, wherein, when the operating members (3A, 3B) are made to slide outward by a biasing force, engaging portions at outer ends of the operating members (3A, 3B) are engaged with to-be-engaged portions in the front end opening, and the cap main frame is attached to the front end opening of the lens barrel, first locking portions are formed at inner edges of the operating members (3A, 3B), and second locking portions are formed on back surfaces of the operating members (3A, 3B), characterised in that: the lens cap further comprises: concave portions formed on the front surface of the cap main frame, the concave portions surrounding outer peripheral surfaces of the operating members (3A, 3B) so as to prevent the operating members (3A, 3B) from protruding outward from an outer peripheral surface of the cap main frame, first openings and second openings are formed in bottoms of the concave portions, the engaging portions of the operating members (3A, 3B) being engaged with a side of the back surface from the front surface through the first openings, the first locking portions of the operating members (3A, 3B) being locked with the side of the back surface from the front surface through the second openings, cover plates (5A, 5B) are placed on the back surface of the cap main frame, the cover plates (5A, 5B) having first to-be-locked portions and second to-be-locked portions, the first to-be-locked portions being locked with the first locking portions of the operating members (3A, 3B), the second to-be-locked portions being locked with the second locking portions of the operating members (3A, 3B), and biasing members are placed between the cover plates (5A, 5B) and the back surface of the cap main frame, the operating members (3A, 3B) being made to slide outward when the cover plates (5A, 5B) are pushed outward by the biasing members. concave portions formed on the front surface of the cap main frame, the concave portions surrounding outer peripheral surfaces of the operating members (3A, 3B) so as to prevent the operating members (3A, 3B) from protruding outward from an outer peripheral surface of the cap main frame, first openings and second openings are formed in bottoms of the concave portions, the engaging portions of the operating members (3A, 3B) being engaged with a side of the back surface from the front surface through the first openings, the first locking portions of the operating members (3A, 3B) being locked with the side of the back surface from the front surface through the second openings, cover plates (5A, 5B) are placed on the back surface of the cap main frame, the cover plates (5A, 5B) having first to-be-locked portions and second to-be-locked portions, the first to-be-locked portions being locked with the first locking portions of the operating members (3A, 3B), the second to-be-locked portions being locked with the second locking portions of the operating members (3A, 3B), and biasing members are placed between the cover plates (5A, 5B) and the back surface of the cap main frame, the operating members (3A, 3B) being made to slide outward when the cover plates (5A, 5B) are pushed outward by the biasing members.