The 17-year-old crossed the line 14 seconds clear of his nearest rival to take victory in the 2016 race at Pont Chateau following an eighth-placed finish last year.
Pidcock hit the front after three laps and held off a chasing pack of riders which included GB team-mate Ben Turner, who eventually finished seventh.
Another Yorkshire rider, 19-year-old Amira Mellor from Holmfirth, placed 20th in the Under-23 European Championship.
Elsewhere, Sheffield University dominated the BUCS National University Hill-Climb Championships in Scotland on Saturday, with their riders winning all four of the main categories.
Racing over a course at Logie Kirk in Stirlingshire that was just under one mile long, Kieran Savage clocked 4min 8sec was six seconds quicker than anyone else on his way to victory in the men’s event, and he headed up the winning trio in the men’s team event with Patrick Clark placing third overall and Archie Cross fifth.
And in the women’s event another Sheffield student Liz Stedman was fastest in 5.35. Sheffield team-mate Holly MacMahon was fourth and joined her in the two-strong winning team from Sheffield, and was just 1.5 seconds away from third place.
In Wakefield, Billy Harding (Oldfield-Paul Milnes) raced to victory in round six of the Yorkshire Cyclo-Cross Series, crossing the line at Thornes Park 19 seconds ahead of his nearest rival. The Bradford 20-year-old held off Nick Barnes (Hargroves Cycles) for the win, while fastest woman was Harding’s Oldfield team-mate Sophie Thackray.