To provide a hydraulic metal machining device transportable in a work site and capable of performing plural kinds of machining.

A hydraulic metal machining device is provided with a lower plate 2, three supports 4, 5 and 6 with the lower end sides thereof fixed to the lower plate 2 in three points forming the vertex of a triangle Y on the lower plate 2, an upper plate 3 fixed to the upper end sides of the supports 4 to 6, a V notch machining upper cutter 24 loaded in a V notch machining hydraulic cylinder device fixed on the upper plate 3 inside the triangle Y such that the V-shaped vertex is positioned oppositely to the support 4 of the front side and a V notch machining lower cutter 10 provided in the lower plate 2 oppositely to the upper cutter 24, and the V notch machining lower cutter 10 is disposed such that lines J1 and J2 where lines along the cutter tip parts 10c and 10d of the lower cutter 10 forming a V shape are extended away from the vertex of the V shape are passed through the outer sides of the adjacent supports 5 and 6 with respect to the triangle Y.