The invention relates to supporting trundles for an electric grid telegraph pole erecting device. The supporting trundles comprises trundle bodies and cylindrical supporting rods connected with the trundle bodies, threads ae arranged on the supporting rods, and nuts cooperating with the threads are arranged on the threads; cylindric trundle covers with openings facing downward are arranged at thelower ends of the nuts, and synchronous pulleys are arranged at the upper ends of the nuts. The axial leads of the synchronous pulleys, the nuts, the trundle covers and the supporting rods coincide;the trundle covers can cover the whole trundles, chamfers are arranged on the end portions of the openings of the trundle covers, and spiral grooves are formed in the outer walls of the trundle covers. The synchronous pulleys on adjacent trundles are connected through a synchronous belt. The adopted synchronous pulleys can achieve the purpose of lowering the two trundle covers synchronously by only rotating one nut, the using is more convenient, the lowering steps of the two trundle covers are consistent, and it can be avoided that when one trundle cover is high, and the other trundle cover islow, the supporting trundles are pushed, so that the bottom end surface of the lower trundle cover is abraded.