According to an aspect, a touch detection device includes: a first substrate; a second substrate opposed to the first substrate; a cover base material opposed to the second substrate; a plurality of first electrodes overlapping a display region on a plane parallel with the first substrate; and a second electrode arranged at the cover base material and overlapping a frame region outside the display region. Proximity or contact of an object with respect to the frame region is detected based on capacitance between the first electrodes and the second electrode. The second electrode extends along a side of the frame region.