The disclosure describes an adapter for a multifunctional electric drill which has a first bearing and a second bearing both disposed in an outer housing. By means of a transmission shaft disposed in the outer housing by using the first bearing and the second bearing, a swinging bearing mounted on the transmission shaft and a sliding rod connected to the swinging bearing, a preset angle is formed between the axis of the swinging bearing and the axis of the transmission shaft. A transmission shaft is fixed by using double bearings, rotation is stable, noise is low, and the service life is long; the rotation movement is converted into the straight reciprocating movement of a sliding rod by means of an inclined swinging bearing, and the energy conversion rate is high.