The magnetic, electrical, and optical properties of the high-entropy equiatomic AlCrFeCoNiCu alloy produced by rapid quenching from the melt by spinning at a cooling rate of 10(5)-10(6) K/s have been investigated in wide ranges of magnetic fields (H a parts per thousand currency sign 90 kOe) and temperatures (2 K < T < 1000 K). The established regularities of the temperature-dependent behavior of the physical properties of the alloy have been discussed taking into account the revealed features of the ultrafine-grained bcc structure of the alloy containing multicomponent nanoclusters and nanophases with the atomic and magnetic orders, chemical composition, and period of the spatial modulation, which change upon heating of the samples.