We report three-dimensional morphological chirality induction using a magnetic field. A right- or left-handed circular helix of zinc silicate membrane tube is selectively formed by application of a magnetic field (5-15 T), whereas the tube grows straight upward at zero field. Square and triangular helixes are also prepared. The results are interpreted in terms of the boundary-assisted magnetohydrodynamics mechanism in which the Lorentz force on ions in solution results in one-way convection of the solution near the boundary.