Two new species belonging to the genus Trhypochthoniellus were described from several mires in northern Japan: T. brevisetus sp. nov. and T. taisetsuensis sp. nov. The Japanese species, described as T. setosus Willmann, 1928 in the past (Kuriki and Aoki, 1989) should be regarded as T. brevisetus sp. nov. according to Weigmann's conception (1997 and 1999) and Subias (2004) by 1) large body size, 2) three pairs of setae (le, in and ex) on prodorsum longer than any other congeneric species, 3) short setae (c₁, c₂, cp, d₁ and d₂) on notogaster, 4) setae h₃ remote from h₂, 5) seta cha on chelicera minute, approximating to seta chb, and 6) lacking of solenidion ω₂ on tarsus II. The species showed some morphological variations between the specimen in low altitude localities and high altitude localities. T. taisetsuensis sp. nov. is distinguishable from any congeneric species by 1) small body size, 2) notogastral surface lacking network-like structure, 3) the small number of genital setae, and 4) long setae on infracapiturum.