A study of inelastic electron scattering from Ca40 at 180°in a momentum transfer range between 0.7<q<2.1 fm-1 has revealed strong excitations of the isobaric analog states of K40. Transition strenghts to the lowest 4-, 3-, 2-, and 5- states with T=1 at Ex=7-10 MeV are extracted. These strengths are compared to the results of inelastic proton scattering and β-decay experiments, and they are proven to be consistent with each other. The experimental values obtained are compared to the energy weighted sum rule values. The transverse magnetic transition strengths of the 4- and 2- states are reasonably well reproduced by a shell-model calculation incorporating the core polarization. The same model, however, is insufficient to explain the transverse electric transitions of the 3- and 5- states.