Secret Police (Himitsu Keiji) agent Yutaka Daimon returns to Japan after learning his father was murdered by the evil Dr. Akunomiya, leader of the criminal gang Sigma (named after the Greek letter). From his father Yutaka inherited the robot warrior Denjin Zaborger which responds to Yutaka's voice commands. Zaborger has the unique ability to transform into a motorcycle, Machine Zaborger, for Yutaka Daimon to ride.
Dr. Akunomiya's top aide in Sigma is a woman known as Miss Borg. She's a cyborg with (in the early episodes anyway) the ability to transform into a masculine appearing robot warrior. Ruling Sigma with Dr. Akunomiya and Miss Borg are the seven Sigma Executives, leaders of Sigma's various world wide operations. These nasty cyborgs eventually fall to Yutaka Daimon and Denjin Zaborger. Serving as Sigma's field agents are Sigma Mecha Animals, Sigma Cyborgs, Sigma Group Hitmen (human assassins), Sigma Mecha Borg, Sigma Borg and Sigma Soldiers. Dr. Akunomiya is a cruel and demanding master. He even turns against his most loyal servant Miss Borg, replacing her with a new female aide Lady Borg. By then Sigma is on its last legs so Lady Borg doesn't last long.
After his cyborgs and robots (even Miss Borg) have failed to eliminate Yutaka Daimon, Dr. Akunomiya assigns the task of getting rid of his greatest enemy to a young assassin, the motorcycle riding Gen Akitzuki. Gen Akitzuki's bird shapped motorcycle is called Machine Hawk. Gen Akitzuki's "Thunder Punch" and "Hurricane Punch" martial arts techniques proved to be a match for Yutaka Daimon's "Flying Dragon Tri-Stage Kick" and gave the hero some tough moments.
After finally defeating Gen Akitzuki, in episode 38, Yutaka Daimon and Denjin Zaborger take out the last Sigma robot, in episode 39, and Yutaka Daimon at last comes face to face with his father's killer, Dr. Akunomiya. However, Yutaka is not the only one interested in the demise of Sigma. Another evil group hiding in the shadows hopes for the elimination of a rival. And so Yutaka Daimon and Zaborger's battle to restore peace in Japan has really just began.
In episode 40, Yutaka Daimon finds himself up against an even more dangerous group the Dinosaur Army (Kyouryuu Gundan). To combat this group Yutaka Daimon is joined by a second, younger (and less skilled) Secret Police agent Ken Matsue who rides a bazooka-armed motorcycle called Machine Baja. Starting with episode 41 Machine Zaborger and Machine Baja merge to form Strong Zaborger, a more powerful version of Denjin Zaborger.
The second half of the series (episodes 40-52) was given the subtitle of Denjin Zabôgâ tai Kyouryuu Gundan which translates to Electroid Zaborger vs. the Dinosaur Army.
The Dinosaur Army is led by an ancient monster, Triple Neck Demon (Majin Mitsu Kubi). It's a three-headed dinosaur or dragon. One head of this ancient beast spits fire, one poison gas and one a bolt of energy. Triple Neck Demon's chief aides are the human worshipers Devil Hat (Akuma Hatto) and Queen Meza (JyouOu Meza). Devil Hat makes the dinosaur shaped robots for the Dinosaur Army and uses his hat like a weapon (he throws it). Queen Meza is an expert at disguises and serves as a spy. Under these three are the Dinosaur Army Mecha (Devil Hat's robots), Dinosaur Army Hitmen (human assassins) and the repitle headed Dragon Face Soldiers.