This is a song that proved somewhat elusive to me, but whenever I hear it on some retrospective or on YouTube, I go "Oh, yeah! I remember this song."
Creation（クリエイション）was a rock band that first launched in 1969 under the name of Blues Creation as a 7-member group with Kazuo Takeda（竹田和夫）as the first guitarist with the late Fumio Nunoya（布谷文夫）and Hiromi Ohsawa（大沢博美）as the co-vocalists. According to the Wikipedia article on the band, Takeda was the "brainchild" for Creation which underwent a number of lineup changes, including at one point in the early 70s when the band was down to just Takeda and bassist Masashi Saeki（佐伯正志）. Takeda himself took over as vocalist in 1971. The band name even changed a couple of times with Blues Creation becoming Bloody Circus for one year between 1971 and 1972 before settling on Creation.
Apparently, Creation only released two singles, both in 1981, with "Lonely Hearts" being the debut. I've only heard one other song by them along with "Lonely Hearts", so I don't really have the impression of them being a hard-driving rock band. Single No. 1 has a sound more reminiscent of 70s hitmakers Godiego: a good ol' laid-back feeling with a sense of folk in the music which was composed by Takeda. The Akira Otsu（大津あきら）-penned lyrics talk about a lonely young turk on the streets of presumably Tokyo looking for love but just as happy walking through the night life.
By the way, the actual singer for "Lonely Hearts" was the late Ai Takano（高野アイ）who had also been with the Group Sounds band, The Carnabeats, back in the 1960s. He stayed with Creation from 1981 to 1984.
"Lonely Hearts" was released in May 1981 and managed to become the 37th-ranked song of the year. The song was also the theme song for a detective show titled "Pro Hunter" starring Tatsuya Fuji and Masao Kusakari. Kusakari is someone these days that I see fairly regularly on TV Japan as a somewhat befuddled navigator of an NHK arts program titled "Kanshou Manual: Bi no Tsubo"（鑑賞マニュアル 美の壺...Appreciation Manual: Vase of Beauty）.