To reduce a time necessary for contracting a glass fine particle deposited body and for making it transparent without causing axis deviation.

The method of heating the glass fine particle deposited body G obtained by depositing glass fine particles on a glass rod G1 and making it transparent includes: a degassing step for heating the glass fine particle deposited body under a reduced atmosphere to remove a gas in the glass fine particle deposited body; a first preliminary contracting step for heating the glass fine particle deposited body G at a temperature in a range within 1,350C and 1,420C until the difference between the outer surface temperature of the glass fine particle deposited body G and the temperature of the boundary of the glass fine particle deposited body G and the glass rod G1 reaches 100C; a second preliminary contracting step for heating the glass fine particle deposited body G at a temperature by 10C and 60C higher than that in the first preliminary contracting step after the preliminary contracting step; and a vitrifying step for making the glass fine particle deposited body G transparent by heating the glass fine particle deposited body G at a temperature in a range of 1,480C and 1,600C after the second contracting step.