PROBLEM TO BE SOLVED: To provide a navigation image in conjunction with tissue deformation in a thermo therapy.SOLUTION: A treatment support apparatus includes: a parameter storage means for storing a treatment parameter for calculating an expansion amount 1104 of a specific portion 1103 of a subject targeted for the thermo therapy an expansion calculation means for calculating an expansion amount of the specific portion by the thermo therapy using the treatment parameter an update image generation means for performing expansion and contraction processing of a three dimensional reconstruction image 1105 based on three dimensional volume data of the subject acquired prior to the thermo therapy based on the calculated expansion amount, and for generating an update three dimensional reconstruction image 1115 that reflects the expansion amount of the specific portion by the thermo therapy and a display means for displaying the update three dimensional reconstruction image 1115.
