Correlations between the changes in martensitic transformation start temperature (M s ) by addition of ternary elements X and several factors of the ternary additions were investigated for TiNi shape memory alloy. The change of M s by addition of 1mol%X is referred to as ΔM s (in K/mol%), and ΔM s was systematically evaluated by differential scanning calorimetry experimentally using (Ti, X)50Ni50 solution-treated at 1273K for 3.6ks where the Ni content was kept constant to be 50mol%. The ternary additions X investigated are the transition metal (TM) elements selected from 4th period group (Zr, Hf) to 10th period group (Pd, Pt). The factors investigated are (1) the number of total outer d- and s-electrons (N ele ), and electron hole number (N V ), (2) electronegativity (E N ), (3) atomic volume (V X ) and (4) Mendeleev number (N M ). It was found that the values of ΔM s are different even in a same period group; ΔM s of 6th period group are -133K/mol%Cr (3d-TM), -152K/mol%Mo (4d-TM) and -64K/mol%W (5d-TM) for example. The results found in the correlations between ΔM s and those factors are summarized as follows. (1) ΔM s depends on N ele and N V . However, the data are scattered because same N ele and N V are often given in a same period group. Then, other factors than N ele and N V are required for clear understanding of ΔM s . (2) ΔM s seems to become lowered slightly with increasing E N . (3) ΔM s weakly depends on atomic volume V X . Ternary addition with large V X increases ΔM s slightly, and with small V X decreases ΔM s largely. Since the stress field must be formed by substitution due to size mismatch, the type of stress field, tension/compression, may be an important role to determine the sign of ΔM s . (4) ΔM s shows a good correlation with N M as -9.4Kmol%−1/ΔN M where ΔN M is the difference in N M . This suggests that a ternary alloying element with smaller (larger) N M stabilizes the B19’ martensite (B2 parent) phase. Effect of site occupancy on M s is also discussed only for Cr.