A panel cart includes a base frame and a supporting frame. The base frame includes a positioning seat. The positioning seat includes an outer surface having a sliding portion and an engaging slot contiguous to the sliding portion. A supporting frame is pivotably mounted to the base frame and pivotable between a folding position and an extended position about a pivotal axis. The supporting frame includes a locking seat and a locking member slidably mounted to the locking seat. The locking member remains in contact with the positioning seat. The locking member abuts against the sliding portion when the supporting frame is in the folding position. The locking member engages with the engaging groove when the supporting frame is in the extended position.