Device to introduce and extract containers with respect to a sterilization machine (100, 100a, 100b) in a direction of feed, comprising - a container-loading plane (P, P', P") defining a movement path, and motorized linear guide rollers (12, 112, 212), supported by a support frame, disposed along the container-loading plane (P, P', P") and configured to move said containers in a guided manner along said movement path in the direction of feed, characterized in that it also comprises - an auxiliary guide extension (13, 113, 213) connected to said container-loading plane (P, P', P") and comprising a frame connected to the support frame, at least one abutment element and auxiliary guide rollers, said frame being slidingly mobile between a first retracted position, in which said frame is comprised in the bulk of the container-loading plane (P, P', P"), aligned or more internal with respect to a front edge of the support frame and in which the auxiliary guide rollers are coplanar with respect to the motorized linear guide rollers (12, 112, 212), and a second operating position, in which said frame is at least partly protruding from the container-loading plane (P, P', P") in order to define an extension of said movement path; - a translator slider (15, 115) mobile in said direction of feed to selectively extract or insert said containers with respect to said machine (100, 100a, 100b), and provided with a thrust element configured to interfere with the bulk of said abutment element and configured to contact said abutment element and automatically thrust said auxiliary guide extension (13, 113, 213) toward the outside of said container-loading plane (P, P', P") in said operating position due to the effect of said contact. - a container-loading plane (P, P', P") defining a movement path, and motorized linear guide rollers (12, 112, 212), supported by a support frame, disposed along the container-loading plane (P, P', P") and configured to move said containers in a guided manner along said movement path in the direction of feed, - an auxiliary guide extension (13, 113, 213) connected to said container-loading plane (P, P', P") and comprising a frame connected to the support frame, at least one abutment element and auxiliary guide rollers, said frame being slidingly mobile between a first retracted position, in which said frame is comprised in the bulk of the container-loading plane (P, P', P"), aligned or more internal with respect to a front edge of the support frame and in which the auxiliary guide rollers are coplanar with respect to the motorized linear guide rollers (12, 112, 212), and a second operating position, in which said frame is at least partly protruding from the container-loading plane (P, P', P") in order to define an extension of said movement path; - a translator slider (15, 115) mobile in said direction of feed to selectively extract or insert said containers with respect to said machine (100, 100a, 100b), and provided with a thrust element configured to interfere with the bulk of said abutment element and configured to contact said abutment element and automatically thrust said auxiliary guide extension (13, 113, 213) toward the outside of said container-loading plane (P, P', P") in said operating position due to the effect of said contact.