The official Xinhua News Agency quoted police as saying the suspect, identified as Feng Zhijun, is a resident of the provincial capital of Taiyuan, and that he had admitted to setting off the Wednesday blasts with homemade devices in front of the office building of the Shanxi Provincial Committee of the Communist Party of China. Police said ball bearings and circuit boards were found at the scene.
Police said they found homemade bombs in Feng's residence and seized the vehicle they said they believe he used at the time of the explosions.
The report said Feng previously served nine years in prison for theft.
Last week, a vehicle ploughed into a crowd in Beijing's Tiananmen Square and police later said it was a terrorist attack planned by ethnic Uighur Muslim extremists from the northwest regions of Xinjiang. The vehicle's three occupants and two more in the crowd died in the incident.