Abstract: An improved guidance device for use with an earthworking machine, more especially a drain tile laying machine, comprising a earthworking element mounted about a pivot connection. This guidance device comprises a signal emitter and two signal receivers mounted on the earthworking element of the machine. The two signal receivers are mounted on the element in a longitudinal spaced apart relation, so as to distinguish between a depth change or an attitude change in the element. The guidance device also comprises operating means including an electronic control circuit and an hydraulic operating circuit for adjusting the attitude or depth of the element depending on the indication given by the signal receivers.