A utensil for agricultural working, comprising a work tool, a fastening device and a support element connected to said work tool, said work tool comprising at least one shaped area (22, 32) designed to be positioned and reversibly connect with said support element by inserting said fastening device into a hole or opening of the support element, wherein said work tool comprises, at said at least one shaped area (22, 32), respective abutment surfaces (60, 61) made on opposite parts of said work tool which allow the insertion and accommodation of at least one portion of said fastening device so that said fastening device can slide in said opening, passing from a locked position to a released position and vice versa, allowing the locking or releasing, respectively, of said work tool to/from said support element, wherein said fastening device comprises: - a head and a central body, wherein said central body has a larger section with respect to the section of said head; characterized in that the fastening device further comprises - a stem connected to said central body, wherein said stem has a smaller section with respect to the section of said central body, wherein said fastening device remains inserted in said opening both in an assembled position, according to which said work tool is restrained to said support element, and in a non-assembled position, according to which said work tool is released from said support element, and wherein said head, in said locked position, abuts on a first of said abutment surfaces, and wherein said central body, in said released position, abuts on a second of said abutment surfaces. wherein said work tool comprises, at said at least one shaped area (22, 32), respective abutment surfaces (60, 61) made on opposite parts of said work tool which allow the insertion and accommodation of at least one portion of said fastening device so that said fastening device can slide in said opening, passing from a locked position to a released position and vice versa, allowing the locking or releasing, respectively, of said work tool to/from said support element, wherein said fastening device comprises: - a head and a central body, wherein said central body has a larger section with respect to the section of said head; characterized in that the fastening device further comprises - a stem connected to said central body, wherein said stem has a smaller section with respect to the section of said central body, wherein said fastening device remains inserted in said opening both in an assembled position, according to which said work tool is restrained to said support element, and in a non-assembled position, according to which said work tool is released from said support element, and wherein said head, in said locked position, abuts on a first of said abutment surfaces, and wherein said central body, in said released position, abuts on a second of said abutment surfaces. - a head and a central body, wherein said central body has a larger section with respect to the section of said head; - a stem connected to said central body, wherein said stem has a smaller section with respect to the section of said central body, wherein said fastening device remains inserted in said opening both in an assembled position, according to which said work tool is restrained to said support element, and in a non-assembled position, according to which said work tool is released from said support element,