Montagny was a test driver for Renault from 2003 to 2005

The 28-year-old former Renault test driver has made seven starts for Super Aguri this season and tested for Toyota at Silverstone last month.

"Franck is an experienced driver who knows the tracks and has a successful record of developing F1 cars," said Toyota team principal Tsutomu Tomita.

"His display at Silverstone confirmed we have made the right decision."

Montagny, who had four retirements in his seven starts in 2006, comes into the team following the departure of Toyota's current testing line-up.

Ricardo Zonta has joined Renault while Olivier Panis has retired.

"I am absolutely thrilled about my move to Toyota," Montagny told his official website.

"To join the ranks of a world-class car manufacturer is a privilege and a great opportunity for my career.

"I intend to make the best of this opportunity in regard to the continuation of my career in F1."