MERGING SUPPORT DEVICE, MERGING SUPPORT SYSTEM, MERGING SUPPORT METHOD, AND COMPUTER-READABLE MEDIUM

A merging support device includes a memory and a hardware processor coupled to the memory. The hardware processor is configured to: execute control of the first vehicle corresponding to behavior when a second vehicle merges into a first lane, based on a vehicle speed and a vehicle position of a second vehicle traveling in a second lane that merges into a first lane in which a first vehicle is traveling; and notify a driver of the first vehicle about information on a control content of the first vehicle by the hardware processor.