To expand a working range of a work by easily calculating a bending locus of an upper blade and a lower blade to bend a work so as to cope with various bending states.

A bend frame 1 is movably arranged at rear of a top die 31 and a bottom die 32 to clamp a work M in the up/down direction, an upper blade 2 and a lower blade 3 to bend the work W are movably arranged on an upper inclined face 1A and a lower inclined face 1B at the inside of the bend frame 1.