Provided is a rearview mirror with concealed and light-transmittable turn signal light, which is applicable to a vehicle to provide a function of a rearview with light reflection achieved with a reflector, and in addition, an outer cover of the rearview mirror is structured to allow for emission of light of turn signal therethrough so as to also provide a function of alarming for driving safety. The outer cover is made of a light-transmitting material and the outer cover has a surface that is subjected to sputtering to form a sputtering-coated film thereon. The outer cover receives therein a light casing, which is fixed to a minor base of the review mirror by fasteners. Electrical wires extend along a rearview mirror bracket to connect to the light base. The mirror base and the light casing are coupled to each other.