The incident occurred during Raksha Bandhan celebrations in the jail.
After the attack, the jail guard was given first aid at the district hospital, but due to his critical condition, he was referred to the All India Institute of Medical Sciences (AIIMS) in Bhopal for further treatment, the official said.
Sub-Divisional Police Officer (SDPO) Pratibha Sharma told PTI that during the Raksha Bandhan celebration, a prisoner named Nilesh Thakur, who was incarcerated on the charges of attempted murder, arrived at the main gate of the jail with a basket of fruits and pressured the guard, Digvijay Singh Tomar, to open the gate.
When the guard did not open the gate, the prisoner fired at him with a country-made pistol hidden in a fruit basket, she said.
The bullet hit Tomar on the left side of his back, in which he was seriously injured and collapsed, Sharma added.
On being informed, Jail Superintendent R K Choure and other guards rushed to the scene and apprehended the attacker, according to her.
The SDPO said the police inspected the site, registered a case, and initiated an investigation.
The circumstances and how the illegal weapon entered the jail are also being investigated, she said.
"This is a very serious matter. Security arrangements inside the jail are being monitored. The role of the jail guards is also being investigated," she said.
When Raisen Jail Superintendent R K Choure was asked about the illegal weapon entering the jail, he said he had no knowledge of it.
He expressed suspicion that since baskets of sweets and fruits were brought inside the jail during the Raksha Bandhan celebrations, the pistol could have been hidden inside them.