may include a hot side layer 12 a cold side layer 13 and a separating plate 11 the hot side layer 12 may be provided with a plurality of first micro channels in which high temperature fluid flows and the cold side layer 13 may be provided with a plurality of second micro channels 13 a in which low temperature fluid flows when viewed in a planar view the hot side layer 12 and the cold side layer 13 forming the unit module 10 u2032 may commonly include end portion surfaces 61 a 61 b 61 c and 61 d in addition to the side surfaces 60 a and 60 b as aforesaid the end portion surfaces 61 a 61 b 61 c and 61 d may be formed in a symmetrical shape with respect to a central arc so as to allow attachment of the high temperature fluid inlet body 20 the low temperature fluid inlet body 50 the high temperature fluid outlet body 30 and the low temperature fluid outlet body 40 all having the same size the hot side layer 12 and the cold side layer 13 may be bonded to each other by interposing the separating plate 11 therebetween thereby sealing the first micro channel 12 a and the second micro channel 13 a respectively thus high temperature fluid flowing within.