The utility model relates to an elastic sealing plug, which is used for solving the problem that the elastic sealing plug used in the needle-free dosing device has a bad rebound effect after being pressed. The elastic sealing plug of the present invention comprises: a stopper and a support tube respectively connected to the two ends of the stop plate； wherein the support tube is divided into a support portion and a weakened portion, the proportion of the support portion being larger than the weakened portion Proportion, and the stop disc has a diameter, the maximum width of the weakened portion in the radial section of the support tube is about 0.5 to 0.8 times the diameter of the support； or the weakened portion is in the radial direction of the support tube The maximum distribution angle on the section is about 70 to 160 degrees.一種彈性密封塞，用以解決習知用於免針加藥裝置之彈性密封塞受壓後回彈效果不佳的問題。本創作的彈性密封塞包含：一擋止盤的兩端分別連接有一塞柱及一支撐管；其中，該支撐管分為一支撐部及一弱化部，該支撐部的比例大於該弱化部的比例，且該擋止盤具有一徑寬，該弱化部在該支撐管的徑向截面上的最大寬度約為該徑寬的0.5~0.8倍；或者，該弱化部在該支撐管的徑向截面上的最大分布角度約為70~160度。
