A watch with a built-in tag that includes a display displaying a time, a metal case having a through-hole in a side surface, a metal crown disposed to enable opening and closing of the through-hole, and a wireless communication device housed inside the case. The crown includes a head located outside the case and coming into contact with the case to close the through-hole, and a shank extending to the inside of the case through the through-hole with one end portion connected to the head and the other end portion located inside the case. When the head of the crown is pulled in a direction away from the case, the head of the crown becomes contactless with the case to enable a reader device located outside the case to read information of the wireless communication device through the crown.