According to google, his net worth is 45 million and he’s the second richest mangaka in Japan, behind only Eiichiro Oda. Could be higher since it’s just a estimative, but I imagine most of it goes to Shueisha.
dragon-ball & dr. slump are so high & he could also still get money for dragon-quest too i think
in the early 80s (when there was only dr. slump i think & that series only had abt 10 volumes or so out at best at the time i think) he was i think the 35th richest person in japan & now he's way below (or so i'd assume with a net-worth of 45 million)? (if i can ask)