Fife-based Burntisland Fabrications (BiFab) has been commissioned by Aquamarine Power to build Oyster 2, a device that harnesses wave power and allows it to be turned into electricity.
BiFab has won a string of recent contracts in the renewables sector, totalling some 10m.
News of the deal comes just a week after Aquamarine raised 11m from multi-national power company ABB and existing shareholders including Scottish & Southern Energy (SSE).
Construction of the new device will take place over the next six months at BiFab's plant at Methil on the Firth of Forth.
The unit will then be taken to the European Marine Energy Centre (EMEC) near Stromness in Orkney for testing during summer 2011.
Martin McAdam, Aquamarine's chief executive, said: "This contract demonstrates the jobs dividend that a thriving marine energy industry can create.
"Strong support from the Scottish and UK governments has enabled our company to leverage significant private sector investment and this is resulting in manufacturing contracts in Scotland and across the UK."
McAdam said the firm was now looking for a "major investment partner" to take its Oyster device through to commercialisation.
Oyster 2 is 50 per cent wider than it predecessor but produces 250 per cent more power. A group of 20 Oyster devices could power 12,000 homes, Aquamarine claimed.
John Robertson, BiFab's managing director, said: "The renewables sector has the potential to create many employment opportunities, and it's products like the Oyster 2 that will be key.
"This is a good opportunity for UK manufacturing and supply industries and an opportunity not to be missed."
BiFab made its name as a fabricator in the North Sea oil and gas industry but has recently been repositioning itself to take on more work from the growing renewable energy industry.
In August, the company won a 2m contract to build a prototype of Norwegian firm Hammerfest Strom's giant underwater turbine at its Arnish manufacturing yard, on Lewis.
SSE bought a 15 per cent stake in BiFab in April for 11m and placed an order for at least 50 "jackets" a year for offshore wind turbines. Jackets are the structures that the turbines stand on in the sea.
At the same time, Scottish Enterprise lent the firm 4m to expand its production facilities at Methil, with a further 2m coming from a Scottish Government regional selective assistance grant.The first in a series of 30 giant platforms for offshore wind turbines rolled out of the Methil yard last December, destined for Vattenfall's Ormonde wind farm off Barrow-in-Furness.
Lena Wilson, Scottish Enterprise's chief executive, said: "Scotland has world-class renewables companies in Aquamarine and BiFab and it's gratifying to see them working together."