A system comprising a first member being an equipment connector, and a second member being a container connector, wherein a lock mechanism for locking engagement between the first member and the second member is provided, wherein the first member includes a barrel section formed in a cylindrical shape and formed with a hole extending through in a radial direction, wherein the second member is insertable into the barrel section from one end of the barrel section, and wherein the lock mechanism comprises: an engaged section formed on an outer surface of the second member; and an engagement member having one end portion fixed to an edge of the hole and long in an axial direction of the barrel section, the engagement member including an operating section formed in another end portion and having a gap with respect to the second member in the radial direction, a fulcrum section formed continuously from the operating section in the axial direction of the barrel section and configured to contact the second member in a state in which the operating section is pressed inward in the radial direction, an engaging section formed continuously from the fulcrum section in the axial direction, formed in a convex shape protruding inward in the radial direction, and engaging with the engaged section in the axial direction, characterized in that the engagement member further includes a deformation section formed continuously from the engaging section in the axial direction and configured to be bent to move the engaging section outward in the radial direction when the operating section is pressed inward in the radial direction, and a fixing section for fixing the engagement member with the barrel section of the first member, wherein the operating section is disposed on the opposite side of the fixing section via the engaging section, and the deformation section is provided between the engaging section and the fixing section. wherein a lock mechanism for locking engagement between the first member and the second member is provided, wherein the first member includes a barrel section formed in a cylindrical shape and formed with a hole extending through in a radial direction, wherein the second member is insertable into the barrel section from one end of the barrel section, and wherein the lock mechanism comprises: an engaged section formed on an outer surface of the second member; and an engagement member having one end portion fixed to an edge of the hole and long in an axial direction of the barrel section, the engagement member including an operating section formed in another end portion and having a gap with respect to the second member in the radial direction, a fulcrum section formed continuously from the operating section in the axial direction of the barrel section and configured to contact the second member in a state in which the operating section is pressed inward in the radial direction, an engaging section formed continuously from the fulcrum section in the axial direction, formed in a convex shape protruding inward in the radial direction, and engaging with the engaged section in the axial direction, characterized in that the engagement member further includes a deformation section formed continuously from the engaging section in the axial direction and configured to be bent to move the engaging section outward in the radial direction when the operating section is pressed inward in the radial direction, and a fixing section for fixing the engagement member with the barrel section of the first member, wherein the operating section is disposed on the opposite side of the fixing section via the engaging section, and the deformation section is provided between the engaging section and the fixing section. an engaged section formed on an outer surface of the second member; and an engagement member having one end portion fixed to an edge of the hole and long in an axial direction of the barrel section, the engagement member including an operating section formed in another end portion and having a gap with respect to the second member in the radial direction, a fulcrum section formed continuously from the operating section in the axial direction of the barrel section and configured to contact the second member in a state in which the operating section is pressed inward in the radial direction, an engaging section formed continuously from the fulcrum section in the axial direction, formed in a convex shape protruding inward in the radial direction, and engaging with the engaged section in the axial direction, characterized in that the engagement member further includes a deformation section formed continuously from the engaging section in the axial direction and configured to be bent to move the engaging section outward in the radial direction when the operating section is pressed inward in the radial direction, and a fixing section for fixing the engagement member with the barrel section of the first member, wherein the operating section is disposed on the opposite side of the fixing section via the engaging section, and the deformation section is provided between the engaging section and the fixing section.