The dielectric and insulating properties of a single Ti0.87O2 nanosheet were investigated by fabricating an Au/single Ti0.87O2 nanosheet/Au planar microcapacitor structure. Capacitance and electric measurements of the nanosheet microcapacitor showed reproducibly good performance as a gate insulator: almost frequency-independent capacitance up to 1 MHz and extremely high electric field endurance of >= 20 MV cm(-1).