We have constructed a one-inch-sized apparatus for gel electrophoresis (mu GE). This apparatus was shown to be of high performance and to have potentials to apply to versatile purposes mainly due to its speed and economy. The temperature gradient gel electrophoresis as well as the conventional gel electrophoresis of multi-wells was successfully performed with both DNAs and proteins. Secondary gel electrophoreses in the two alternative modes, band-cut and zone-cut, were shown to be operable.