The man, the owner of a small firm in the Moscow Region, held his girlfriend at gunpoint in his car, threatened to kill her and blow up the vehicle, pointing at a device that he said was a home-made bomb.
Police later said "no explosive device was found in the car" and the weapon appeared to be a gas powered pistol.
After police officers stormed the vehicle the female hostage was released "uninjured," the spokesman added.
"They had been living together in a common-law marriage. The woman said he had constantly been jealous of her," the police spokesman said.
A police source said that the hostage taker had made no demands. An investigation has been opened into the incident.