The invneiton relates to an electronically controlled internal damper. The electronically controlled internal damper includes: a main passage formed by a working fluid flowing through a main piston; an ignition passage formed by a working fluid as much as a predetermined amount discharged from a first ignition chamber and a second ignition chamber so as to maintain internal pressures of the first ignition chamber and the second ignition chamber to a predetermined level when pressures of the first ignition chamber and the second ignition chamber are increased beyond the predetermined level; and a bypass passage formed by a working fluid passing through the compression retainer and the rebound retainer symmetrically disposed above and under the main piston and a plurality of holes formed transversely to a vertical length direction of a spool rod. Accordingly, the electronically controlled internal damper is capable of implementing damping performance in both a soft mode and a hard mode with a relatively simple structure and increasing sealing performance while reducing rigidity.