A radio-controlled timepiece with an internal antenna provides an improved arrangement within and appearance to a case member of the timepiece that reduces manufacturing cost and affords a smaller timepiece. The antenna, which has a core and coil wound around the core, is rendered inside the case member such that both end portions of the core, and preferably the entire core, are disposed along a curved inside surface of the case member. Because the end surfaces of the core do not oppose the inside surface, the antenna can be located close to the case member without a drop in antenna performance. The case member can therefore be made of metal to give the timepiece a better design and appearance. With such an arrangement, production cost can be reduced because notches need not be formed in the case, and the timepiece can be made smaller.