A miniature inductor used as a boosting coil in a piezoelectric buzzer drive circuit or the like is disclosed. The inductor has a closed magnetic circuit core formed of two cores covering the outer periphery of a coil wound around inner coil-cores. A pair of cutout windows are provided at the outer periphery of each of the cores, and joint plates are disposed on the inner bottom surface of one core. Terminal blocks project outwardly therefrom, so that the terminal blocks are adapted to be folded over each other. The end of each lead wire of the coil is guided through the cutout window and sandwiched between the folded terminal blocks, thereby connecting therewith.