Provided are a valve filler and a valve unit including the valve filler. The valve filler includes: a phase transition material; and a heating fluid comprising a carrier oil and a plurality of micro heating particles suspended in the carrier oil, the heating fluid being mixed with the phase transition material, wherein, when external energy is supplied, the micro heating particles receive the external energy and generate heat to melt the phase transition material into a fluid state, and when no external energy is supplied, the phase transition material hardens into a solid state.