A vortex generator device for a wind turbine blade, and a wind turbine blade is disclosed, the vortex generator device comprising a base with an inner side and an outer side, and a first fin protruding from the outer side and extending along a first fin axis, wherein the vortex generator device is a single-fin vortex generator device, and the base has a first edge part and a second edge part, the first edge part and the second edge part forming a primary angle in the range from 5 degrees to 60 degrees.