To provide a magnet unit capable of efficiently increasing magnetic force (magnetic flux density), by reducing a leakage magnetic flux.

This magnet unit has a U-shaped yoke 20 composed of a ferromagnetic substance, being a cross-sectional rectangular shape and formed by bending a bar-shaped raw material in a U shape, and two magnets 10 and 10 opposing different magnetic poles by being attracted inside in the vicinity of both ends 20a and 20b of the U-shaped yoke 20, and is characterized by having a clearance W between both magnets. A step height 20c is formed on a surface for attracting the magnets 10 and 10 of the U-shaped yoke 20, and may be constituted by arranging a clearance (d) between the step height and the magnets.