Well known Japanese brand from the Japanese Matsushita company. Also used the name "National Panasonic" and made calculators for Olympia.
Panasonic was one of the first entrants into the field of pocket computers. More recently, what appears to be a Canon OEM programmable model (although in a different style housing) was released under the Panasonic brand name.
Since the end of 2014 Mastushita Co. is named Panasonic Corp., the brand National disapears.
Source : vintagecalculators.com & epocalc