Leakage-proof well drilling device

The invention relates to a leakage-proof well drilling device which comprises a drill string, a supporting and adjusting device, a drill bit and a leakage-proof elastic pipe capable of shrinking or expanding in the radial direction, the supporting and adjusting device comprises a plurality of supporting and adjusting assemblies, and the supporting and adjusting assemblies are connected through connecting pieces. Each supporting adjusting assembly comprises a supporting sleeve arranged on the outer side of the drill pipe column in a sleeving mode at intervals and at least one elastic supporting ring arranged on the outer side of the supporting sleeve in a sleeving mode at intervals and capable of contracting or expanding in the radial direction, and a driving device capable of driving the elastic supporting ring to contract or expand in the radial direction is arranged between the supporting sleeve and the corresponding elastic supporting ring. An upper protruding ring and a lower protruding ring which can lim