Cryopump and regeneration method

The present invention provides a cryopump and regeneration method, object of the present invention is to promote the discharge of the water in the regeneration of the cryopump. Cryopump regeneration method of the present invention includes: a first discharge step (S12), comprising alternately supplied exhaust gas and purge the cryopump in the pressure vessel of the first range; second discharge step (S18), comprising cryopump vessel is vented to below the low-pressure region of the first pressure range. The second step of discharging comprising the steps of: determining whether the first end of the second step of discharging at least a low pressure region; and determines whether or not prior to the first end of the second discharge step, purge gas is supplied to the cryopump.