A heat exchanger module unit that provides heat exchange between a fluid and a heat medium by indirect heat exchange through a phase-change material disposed between movement paths of the fluid and the heat medium movement paths, includes: a multiple number of plates having a partition, which is formed with a through-hole through which the fluid and the heat medium move, are stacked with a spacing gap, through which the fluid and the heat medium move, at one side of the partition; the spacing gaps are selectively connected through a connector connecting the respective through-holes so as to form a fluid passage and a heat medium passage through which the fluid and the heat medium move independently respectively; the spacing gap, in which the phase-change material is received, is located and disposed between the spacing gaps forming the fluid passage and the heat medium passage through which the fluid and the heat medium move respectively such that heat exchange is made between the fluid and the heat medium through the phase-change material. One of the fluid and the heat medium is disposed at one side of the phase-change material and another phase-change material is disposed at the opposite side thereof.