Bead core and pneumatic tire using the same

A bead core (11) is formed by spirally winding a single cord (13) and stacking spiral windings (15) to each other, wherein a winding start end (M) of the single cord (13) is shifted from an axially outermost or innermost position of a radially innermost first stage to a next position at least corresponding to only one of the single cord in the stacking of the spiral windings.