High-entropy alloys (HEAs) are generally multicomponent solid-solution alloys with five or more elements that are close to the isoatomic composition ratios. HEAs are solid solution alloys whose entropy (the configuration entropy, ΔS_conf., the same as the entropy of mixing in ideal and regular solutions, ΔS_mix) is equal to or above 1.5R (R is the gas constant). HEAs are metallic materials that are designed based on “elemental multiplicity and heterogeneity,” rather than on “the characteristics of a single element”. From the perspective of mixing a wide variety of constituent elements at the atomic level, the melting and solidification techniques, in the other words “casting,” is the basic method used in the preparation of specimens and engineering products, therefore, HEAs can be recognized as a new type of casting metallic material. In this review, we introduce some examples of the research on and development of high-entropy casting alloys, especially with respect to public research and testing institutes in Japan.