A flexible bimodal sensor includes a gate electrode; a flexible substrate; a source electrode disposed on the flexible substrate; a drain electrode disposed on the flexible substrate apart from the source electrode; a channel layer disposed on the source electrode and the drain electrode and a portion of the flexible substrate between the source electrode and the drain electrode; and a gate insulating layer comprising a plurality of protrusions, the gate insulating layer being disposed on the channel layer and arranged between the channel layer and the gate electrode. The drain electrode outputs a current signal simultaneously indicating a temperature value and a pressure value sensed by the flexible bimodal sensor.