  Primordial black hole formation by cosmic string collapse is reconsidered
when the winding number of the string is larger than the unity. The line energy
density of the multiple winding string becomes greater than that of the single
winding string so that the probability of the black hole formation by the
string collapse during the loop oscillation would be strongly enhanced.
Although the production of the multiple winding defect is suppressed and its
number density should be small, the enhancement of the black hole formation by
the increased energy density may provide a large number of evaporating black
holes in the present universe which gives more stringent constraint on the
string model compared to the ordinary string scenario.
