To provide a reinforcing structure for an existing building capable of reducing the number of anchor reinforcements while preventing a punching rupture at a column end part in an earthquake so as to reduce a part cost and a construction cost and also suppressing, in a short period, vibration and noise caused by the installation of the anchor reinforcements.

When a post-placing concrete is placed, a number of anchor reinforcements 14 are buried between a quake resisting wall 12 and a beam 11 to form the quake resisting wall 12 integrally with the beam 11, whereas, the anchor reinforcements 14 are not provided between the quake resisting wall 12 and columns 10 and clearances K are provided so as to form a non- integral structure. An interstitial member 13 is provided at the upper and lower end parts between the quake resisting wall 12 and the columns 10.