A steel for induction hardening includes as a chemical composition, by mass %, C: 0.45% to 0.85%, Si: 0.01% to 0.80%, Mn: 0.1% to 1.5%, Al: 0.01% to 0.05%, REM: 0.0001% to 0.050%, O: 0.0001% to 0.0030%. Ca: 0.0050% or less as necessary, Ti: less than 0.005%, N: 0.015% or less, P: 0.03% or less, S: 0.01% or less, and the balance consists of Fe and impurities. The steel for induction hardening also includes a composition inclusion which is an inclusion containing REM, O, S, and Al, or an inclusion containing REM, Ca, O, S, and Al, to which TiN is adhered.