The utility model provides an adjustable guide tube connecting device which comprises a support, a spherical adjusting device and a filler neck, wherein the spherical adjusting device comprises a spherical joint, a spherical nut, a spherical base and a corresponding fastener. According to the adjustable guide tube connecting device, the rotation characteristic of the spherical joint is utilized, so that parts such as the spherical base, the spherical nut and the filler neck are integrated in one device, and fixation of guide tubes with different spatial trends is realized. The device has the advantages of simple structure, large adjustment range, good generality, convenience in operation, reusability and the like.