The invention relates to a stepless height adjusting type built-in type vibration isolating device which comprises a connection sleeve and an elastic vibration isolator, and further comprises a height adjusting thread piece, threads are arranged in at least partial inner surface of the connection sleeve and at least partial outer surface of the height adjusting thread piece correspondingly, the connection sleeve and the height adjusting thread piece are connected in fit mode through the threads, and at least part of the height adjusting thread piece is arranged above the elastic vibration isolator. The vibration isolating device solves the problem existing in the prior art that inconvenient maintenance and adjustment are brought by solidified connection or integrated arrangement of a support stop block and a floating plate; and the stepless height adjusting type built-in type vibration isolating device which can truly achieve precise height adjusting of the floating plate and more convenient maintenance and change depending on the thread structure without the need for arranging a height adjusting spacer is provided, not only can be applied to all kinds of track transit floating ballast bed structures, but also can be widely applied to industry rotation equipment elastic vibration isolation foundation engineering and other fields, and has broad market application prospects.