Tank cooling apparatus

A cooling apparatus for cooling a hollow tank made of a thermoplastic synthetic resin, the cooling apparatus comprising:

• a pair of movable frames provided to be movable relative to each other so as to clamp the tank;
• multiple contact members provided on each of the pair of movable frames and each having a contact surface configured to contact an outer surface of the tank;
• a cooling liquid supply passage provided with multiple cooling liquid supply ports that respectively open in the contact surfaces of the contact members to supply a cooling liquid toward the outer surface of the tank;
• and
• a cooling liquid supply device that supplies the cooling liquid to the cooling liquid supply passage,
• wherein each of the contact surfaces is provided with grooves extending from a corresponding one of the cooling liquid supply ports to an outer edge of the contact surface.