The invention relates to a fitness device for exercising the lower limbs, characterised in that the pedals (112), the frame (12) and the various means (13) for articulation, pressure resistance and pedal-restoring, are designed as a single component, consisting of at least one single plate (1) in an elastic material in a V shape with a rounded apex or a U shape with parallel or flared branches, one of the branches (11) thereof being provided with an opening (111) opening up at the base of the "V" or the "U", for forming the two pedals (112), the other branch (12) thereof forming the frame for the two pedals, and each rounded apex (13) thereof that connects each pedal (112) to the frame (12) forming, as a single component, the means for articulation, pressure-resistance and restoring each pedal.