In most parts of the country, polling stations will close at 8:00 p.m. local time and vote counting will start as soon as the voting ends.
Members of the upper house serve six-year terms, with about half the seats up for grabs every three years.
In Sunday's election, 124 seats are up for grabs, including three that are newly added.
With a total of 370 candidates vying for the seats, key platform issues include amending the Constitution, hiking the consumption tax, and the state's pension system.Abe has said his victory line for his Liberal Democratic Party and its coalition partner Komeito is to maintain a majority, or 123 seats, of the slots in the 245-seat chamber.
Holding 70 of the seats in the uncontested half, the coalition needs to win 53 to keep control of the upper house.