The invention relates to the technical field of sports goods, and discloses an inflating device capable of ensuring constant inflating content based on intermittent reciprocating motion. The device comprises a pedestal for supporting a ball; via the matched use of a first rotation shaft, a second rotation shaft, an inflating pipe, a first limiting block, a second limiting block and a support bar,when the first rotation shaft is rotated, the inflating pipe is driven to synchronously do leftwards and rightwards intermittent reciprocating motion, to complete inflating and stop inflating, and motion time is accordant, so that an inflating volume is kept constant, and quality of a football is prevented from being damaged by insufficient inflating or excessive inflating; and via the matched useof the first rotation shaft, the second rotation shaft, the support bar and the inflating pipe, the football is relatively hard, the volume of the football before inflating and after inflating is notlargely changed, artificial judgment may have a relatively large error, a traditional artificial judgment mode is changed for inflating, the work intensities of people are relieved while the qualityof the football is ensured, and work efficiency is improved.