A position adjustment device for a vehicle rearview mirror adjusts the linear distance between the rearview mirror and the vehicle body to which the rearview mirror is configured. A driver may use the position adjustment device to adjust a visibility range according to driving needs. The position adjustment device includes a mounting unit and a length adjusting unit. The mounting unit is used to combine together with a vehicle body. The length adjusting unit has an end coupled with the mounting unit by a combining unit and an opposing end combined with a vehicle rearview mirror by a joining unit.