A reactor apparatus for a railway vehicle includes a coil assembly, a side cover, through bolts inserted into the coil assembly, cover supporting members, a pair of frames, and ribs that reinforce the pair of frames. A support/fixation section of each frame is fixed to an under surface of a vehicle pedestal. The pair of the frames are disposed on both sides of the coil assembly, and support the through bolts and the cover supporting member. For each rib, leg members that extend from corresponding reinforcing body are penetrated into and welded to the corresponding frame. For each cover supporting member, a leg member that extends from corresponding cover supporting body is penetrated into and welded to the corresponding frame.