A bushing temperature controller includes a transformer 3 which supplies a
main current I1 to the bushing 2 for accommodating molten glass, and
regulation current supply units 7 and 8 which are adapted to supply
regulation currents I2 and I3 either in phase with the main current I1 or
in phase inverted to the main current I1 to a portion of a region to
which the transformer 3 applies the current. Thus, the temperature
control of partial regions 2a and 2c in the region to which the current
is applied can be performed in a wide temperature range.