A driving force transmission device of a vehicle includes: a main body; a carrying up gear; a drive shaft; and a blocking member. A gear that transmits a driving force to the vehicle is housed in the main body. The carrying up gear carries up a lubricating oil stored in the main body. The drive shaft has, in the shaft, a lubricating oil storage space into which the carried up lubricating oil is introduced and a lubricating oil discharge hole through which the lubricating oil in the lubricating oil storage space is supplied to a bearing unit. The blocking member blocks the lubricating oil discharge hole in accordance with a rotational speed of the drive shaft.