A heart inner wall checking device 100 comprises heart inner wall checking tool 1, and shaft-shaped imaging tool 5, which can be inserted into heart inner wall checking tool 1. Heart inner wall checking tool 1 comprises tubular main body 2, and an inflatable balloon 3, which is provided on the distal end of tubular main body 2. Heart inner wall checking tool 1 also comprises liquid injection port 42 for injecting an inflation liquid into balloon 3 and imaging member port 43 for inserting shaft-shaped imaging member 5, with which a rear side area can be checked. Balloon 3 has transparency, which enables imaging of the outside of balloon 3 with area image sensor 51, and includes balloon rear portion 32, which is capable of coming into close contact with the heart inner wall during inflation. Balloon rear portion 32 includes liquid-exudable member 33, which exudes the inflation liquid and supplies the inflation liquid between balloon rear portion 32 and heart inner wall 12.
