Nicholas Burke, 46, was caught using the device, which is capable of preventing speed readings from being taken by scrambling a signal from a safety camera van, North Yorkshire Police said.
The motorist, who was working at a Ferrari dealership in Leeds at the time of the offence, is believed by police to have been travelling above the 60mph speed limit in a BMW 335D on Greengales Lane, a rural road on the outskirts of York, on February 18 last year.
The jammer prevented the safety camera on the road from taking a reading, but activated a code which indicated to police that a device was being used illegally inside the vehicle.
Burke, who resigned from his role following the incident, is said to have told officers he used the device because he was worried about getting points on his licence.
The defendant, of The Green in Stillingfleet, York, pleaded guilty to perverting the course of justice and was sentenced to two months behind bars by a judge at York Crown Court on Thursday, North Yorkshire Police said.
Andy Forth, a traffic constable with the force, said following the sentencing: "As Burke's prison sentence shows, the courts take a very dim view of people who use jammer devices to pervert the course of justice.
"As such, we have a duty to investigate when we think someone has used one illegally and we will uphold the law.
"So if you use one of these devices in North Yorkshire there's a very strong chance you'll be caught.
"The purpose of our enforcement fleet is to reduce road casualties.
"Therefore to use such devices to interfere with speed enforcement - one of the main four causes of fatal and serious-injury collisions - increases the risk to everyone else who uses the county's roads, and the communities they represent."