The present invention provides an anesthetic solution filled cartridge type electric syringe for dentistry, wherein a plunger is further shortened but the plunger can still be driven forward to a distance necessary to discharge the anesthetic solution from the cartridge. The anesthetic solution filled cartridge type electric syringe for dentistry according to the present invention comprises: an extension tube (11), which is movably disposed in a through hole (14) of a support block (13) to be movably inserted therein with a plunger (5) and has racks (15, 15) formed on the side surface integrated with a rack (9) of the plunger (5) and a means for drawing the extension tube, which is a means for the plunger to draw the extension tube for engaging the racks (15, 15) of the extension tube with a pinion (21) when the plunger reaches the middle of the distance corresponding to the anesthetic solution accommodation length of the cartridge. With the engagement between the racks of the extension tube and the pinion, the plunger moves together with the extension tube for the remainder of the distance corresponding to the anesthetic solution accommodation length of the cartridge.本發明提供一種齒科用麻醉液充填卡匣式電動注射器,其更縮短按壓棒,儘管如此仍可將按壓棒送出從卡匣排出麻醉液所需之距離。本發明之齒科用麻醉液充填卡匣式電動注射器包含:延伸管(11),其係移動自如地設置在支承塊(13)的貫通孔(14),按壓棒可移動地被插入,且側面具有與按壓棒(5)的齒條(9)整合所形成之齒條(15、15);以及拉引延伸管的手段,其係當按壓棒到達相當於卡匣的麻醉液收容長度之距離的中間時,按壓棒為了使延伸管的齒條(15、15)與小齒輪(21)嚙合而用於拉引延伸管的手段;前述按壓棒係藉由延伸管的齒條和小齒輪之嚙合,而與延伸管一起移動相當於前述卡匣的麻醉液收容長度之距離之中剩下的距離。1...電動注射器2...注射器本體3...連接器4、12...安裝塊5、6...按壓棒7...支承體8...抵接體9、15...齒條11...延伸管13...支承塊14...貫通孔19...半徑方向外方突起20...肩21...小齒輪22...手段23...保持孔24...卡止球25、28...凹部26、27...擋止環29...限制開關
