Confirmation of the conditions of the ossicles is essential for tympanoplasty. However, at present, ossicular mobility is experimentally estimated with palpation by a surgeon, and the results depend on the surgeon's skill. In this study, a new apparatus for quantitatively measuring ossicular mobility was developed. With this apparatus, the ossicles were displaced and the reaction force from the ossicles, (i.e. the load applied to the ossicles) was simultaneously detected. Ossicular mobility of three patients with otosclerosis or chronic otitis media was measured to evaluate the usability of the apparatus. The apparatus can distinguish the differences in ossicular mobility between normal and fixed ossicles, and it makes estimating the change of mobility between pre- and posttreatments for ossicular fixation possible. Positive correlation was seen between ossicular mobility and hearing level.