Masaru Tomita was born on October 11, 1946 in Osaka, Japan. He would become a two-time All-Star player in 12 seasons in Nippon Pro Baseball.
Tomita hit .302 when he played at Hosei University. He then was picked in the first round of the 1968 draft by the Nankai Hawks. He hit .246/.323/.434 in 75 games, splitting shortstop with Kenji Koike and backing up Yasuhiro Kunisada at third base as a rookie in 1969. In 1970, he replaced Kunisada at the hot corner and was a sophomore sensation, setting career highs in runs (95, leading the Pacific League), homers (23) and RBIs (81). He hit .287/.368/.485, drew 61 walks, was 10th in the league in average and tied Michiyo Arito and Toru Ogawa for the most triples (five) in the Pacific League. He made his first PL All-Star team but lost the Best Nine at the hot corner to Arito.
In 1971, the Osaka native fell to .273/.328/.447 with 13 home runs and 12 steals in 15 tries. He performed worse (.247/.314/.377) in reduced action (85 games) in 1972. That off-season, he was traded to the Yomiuri Giants for Akio Matsubara and Shinichi Yamauchi, a deal that worked out badly for Yomiuri. In 1973, the 26-year-old produced at a .188/.235/.391 rate in 73 plate appearances as the backup to legendary Shigeo Nagashima. Nagashima was out of commission for the 1973 Japan Series, though, and Tomita stepped in. He was three for 16 with two walks, a double, four runs and a RBI in five games as the Giants beat his old Nankai club. It was the last of a record-setting nine straight Japan Series titles for Yomiuri and Tomita's lone Japan Series appearance.
Tomita was a part-time middle infielder in 1974 and produced at a .265/.343/.407 clip. With Nagashima retiring, Tomita was not given the starting third base job, as the Giants brought in Davey Johnson. Tomita wound up batting only .189/.267/.235 in 224 plate appearances as a backup SS/3B in 1975.
Yomiuri traded Tomita with Kazumi Takahashi to the Nippon Ham Fighters for the great Isao Harimoto after Masaru had failed to hit the Mendoza Line in two of his three seasons in the Central League. He hit .284/.347/.424 with 10 home runs in 1976, his first year back in the Pacific League. In 1977, he hit .307/.372/.452. He was sixth in the circuit in average, between Hiromitsu Kadota and Yutaka Fukumoto; Arito again won Best Nine honors at third.
The veteran remained steady at .307/.387/.440 in 1978 and made his second All-Star team, eight years after his first. He was eighth in the Pacific League in average, between Koji Minoda and Masahiro Doi. Bobby Marcano won Best Nine honors at second base (where Tomita played in '78). He hit .280/.350/.425 with 12 doubles and a career-high 28 doubles in 1979 while moving to the outfield, where he played alongside Makoto Shimada and Bobby Mitchell. He stole a career-high 23 bases (in 29 tries) and scored 76 runs.
In 1980, the 34-year-old slumped to .240/.315/.373 and was 12-for-15 in steal attempts. He was then traded to the Chunichi Dragons for fellow old-timer Hiroaki Inoue. Tomita hit .238/.261/.319 in 92 games to wrap up his career.
Overall, Tomita's stats included 194 doubles, 107 home runs and 126 steals (in 173 tries) over 1,303 NPB games. He hit .270/.340/.415 in 4,558 plate appearances.
After retiring from his career in baseball, he entered the restaurant business.