We deal with a nonlinear hyperbolic scalar conservation law, regularized by the total variation flow operator (or 1-Laplacian). We give an entropy weak formulation, for which we prove the existence and the uniqueness of the solution. The existence result is established using the convergence of a numerical approximation (a splitting scheme where the hyperbolic flow is treated with finite volumes and the total variation flow with finite elements). Some numerical simulations are also presented.Keywords: Bingham fluid, hyperbolic scalar conservation law, total variation flow, 1-Laplacian, entropy formulation, finite volumes, finite elements A Bingham fluid, also called rigid viscoplastic fluid, is a material that behaves as a rigid solid below a certain stress yield and as a viscous fluid above this yield; a familiar example of such a material is the tooth paste. For a d-dimensional Bingham fluid, the relation between the stress tensor σ , seen as a d × d matrix, the pressure p and the velocity u is When the viscosity becomes negligible (ν = 0), the analytical and numerical framework described above is no longer suitable -let us mention however an existence result in 2D obtained by Lions (1972). Although the study of inviscid Bingham fluids has been initiated in Bouchut et al. (2012) with the case of an unsteady flow without convection term, the presence of a nonlinear convection term is naturally issued from the inertial term in the momentum conservation equation. Unfortunately, the study of this problem seems to be out of reach in the actual state of the art, and we only consider here a simplified model of unsteady Bingham flow with convection. This simplified model is scalar and consists in †