To provide an amorphous alloy having low magnetostriction and superior heat resistance, also having high electric resistance, minimal in overcurrent loss, excellent in amorphous substance forming capacity, and capable of easily producing amorphous moldings even under the cooling condition of slow cooling like that in a casting process, etc.

This amorphous alloy has a composition represented by formula Co100-x-y-z-wTxMyLzBw [where T is Fe and/or Ni, M is one or ≥2 elements among Ti, Zr, Nb, Ta, Hf, Mo, and W, L is one or ≥2 elements among Cr, Mn, Ru, Rh, Pd, Os, Ir, Pt, Al, Ga, Si, Ge, C, and P, and also 0≤x≤30 (atomic %), 5≤y≤15 (atomic %), 0≤z≤10 (atomic %), and 15≤w≤22 (atomic %) are satisfied]. Further, (x) satisfies 14≤x≤21 (atomic %), and the difference ΔTx between the glass transition point Tg and the initial crystallization temp. Tx is ≥20K. Moreover, M is represented by (M'1-c M"c), where M' is Zr and/or Hf and M" is one or ≥2 elements among Ti, Nb, Ta, W, and Mo and (c) satisfies 0.2≤c≤1. This alloy has the glass transition point Tg.