Abstract: In well drilling, and in particular the horizontal drilling field, a simultaneous drilling and casing device is provided. A drill string driven in rotation by a revolving table has at its end a drilling tool 28 driven by a bottom motor 22 and, in its intermediate part, a drive connection 10 to which the rear end 1a of a casing section 1 is screwed, whose front end is provided with an abrasive material ring 3. The length of the part of the drill string separating the connection 10 from tool 28 is substantially equal to the length of section 1. The casing 1 driven by the drill string at the speed of rotation of the revolving table cuts its own way during the drilling.