The firm said it would shortly announce a deal with another major manufacturer of minis.
Molson chairman Bob Barnett said: “We have worked well together for almost three years but both companies have now decided that their futures lie in different directions.
“We would like to take this opportunity to reassure existing customers of our continued support for their Kubota products in the future.”
He added: “We will shortly announce an exciting new mini-excavator partnership which will allow the company to continue to provide customers with high quality machines, over a much wider geographic area, with our well-known excellent customer care, after-sales service and support.”
Molson are one of the largest independent dealers in the UK selling around 1,000 machines a year. They are a main dealer for Hyundai.