Ito Electric Machinery Works. (Chukyo, Nagoya), 1945-1955
According to an article posted on the Yaplog web site written by Kazuya Tomisato, a gentleman by the name of Yoshikichi Ito managed to go into the production of an electric motorcycle called the 'Swallow' in 1945. He initially used components from a wrecked American B-29 bomber to build his first one.
Swallows could be operated for about 40 km at a maximum speed of 20 km/h and required about 8 hours of charging. He states that they were popular with doctors as they were clean, quiet and very smooth to ride.
I have so far been unable to find other sources to corroborate this information, but will keep looking.