Folding bed capable of being horizontally placed

The utility model provides a folding bed capable of being horizontally placed. The folding bed comprises a positioning unit; the bed board comprises a front bed board and a rear bed board; the frame assembly comprises a front frame assembly and a rear frame assembly, the front frame assembly is fixed to the front bed board, the rear frame assembly is fixed to the rear bed board, and the front frame assembly and the rear frame assembly are connected in a foldable mode through a connecting unit, so that the folding bed capable of being horizontally placed has a folded state and an unfolded state; the front bed board comprises a first bed board and a second bed board, the first bed board is hinged to the second bed board, the rear bed board comprises a third bed board, a fourth bed board and a fifth bed board, and the third bed board, the fourth bed board and the fifth bed board are sequentially hinged; a first fixing part is arranged on the second bed board, a second fixing part is arranged on the third bed boa