LOCKUP CONTROL DEVICE AND LOCKUP CONTROL METHOD FOR VEHICLE POWER TRANSMISSION DEVICE

Provided is a lockup control device and a lockup control method for a vehicle power transmission device (16) provided with a fluid transmission device (20) including a lockup clutch. The lockup clutch is controlled to perform slip-engagement such that a differential rotation between an input-side rotating member and an output-side rotating member of the fluid transmission device (20) is a target differential rotation set in advance, and the target differential rotation is corrected based on transition of a heat accumulation amount applied to friction members of the lockup clutch.