An upper tool holder for a press brake for holding an upper tool of the press brake, comprising: a holder body; an upper tool clamper that is provided on the holder body, and capable of swinging in an open-close direction when replacing the upper tool; a drop prevention piece that is provided at a lower portion of the upper tool clamper, and capable of engaging with a drop prevention groove formed on the upper tool; an engagement recess that is provided on one of an upper portion of the upper tool clamper and the holder body; an engagement protrusion that is provided on another of the upper portion of the upper tool clamper and the holder body, and capable of engaging with the engagement recess; characterized by an auxiliary urging mechanism that functions as resistance when opening the upper tool clamper further in order to replace the upper tool, and functions so as to support a closing operation when closing the upper tool clamper from a further opened state; wherein the auxiliary urging mechanism includes a pusher and an elastic member that urges the pusher in the closing direction, the pusher stays at a home position in an ordinary state regardless of an opening or closing operation of the upper tool clamper, the upper tool clamper is capable of being opened to a clamped state where fully closed and fixedly holds the upper tool, an unclamped state where opened from the clamped state and holds the upper tool slidably, and a vertically-replacing state where further opened from the unclamped state and the upper tool can be replaced vertically, the ordinary state is a state where the upper tool clamper is in the clamped state or the unclamped state, and the pusher pushes the upper clamper in a state other than the ordinary state. a holder body; an upper tool clamper that is provided on the holder body, and capable of swinging in an open-close direction when replacing the upper tool; a drop prevention piece that is provided at a lower portion of the upper tool clamper, and capable of engaging with a drop prevention groove formed on the upper tool; an engagement recess that is provided on one of an upper portion of the upper tool clamper and the holder body; an engagement protrusion that is provided on another of the upper portion of the upper tool clamper and the holder body, and capable of engaging with the engagement recess; an auxiliary urging mechanism that functions as resistance when opening the upper tool clamper further in order to replace the upper tool, and functions so as to support a closing operation when closing the upper tool clamper from a further opened state; wherein the auxiliary urging mechanism includes a pusher and an elastic member that urges the pusher in the closing direction, the pusher stays at a home position in an ordinary state regardless of an opening or closing operation of the upper tool clamper, the upper tool clamper is capable of being opened to a clamped state where fully closed and fixedly holds the upper tool, an unclamped state where opened from the clamped state and holds the upper tool slidably, and a vertically-replacing state where further opened from the unclamped state and the upper tool can be replaced vertically, the ordinary state is a state where the upper tool clamper is in the clamped state or the unclamped state, and the pusher pushes the upper clamper in a state other than the ordinary state.