PURPOSE: To provide a bed mechanism for interlocking back- and knee-elevating operations which makes elevation of knees possible by interlocking with elevation of the back.

CONSTITUTION: A constitution is made in such a way that a back bottom 2a in a bed 1 is supported through a rotatably mounted back-elevating arm 4 and on the other hand, a knee bottom 2c and a leg bottom 2d are supported through a rotatably mounted knee-elevating arm 5. The rotating shaft 7 of the back-elevating arm 4 is connected to a starting mechanism 9 for displacing up and down the back-elevating arm 4. In addition, the rotating shaft 7 of the back-elevating arm 4 is connected to one end side of the first interlocking lever 14. A long arm 15a of a displacement link 15 is connected to another end side of the first interlocking lever 14 and one end side of the second interlocking lever 16 is connected to a short arm 15b of this displacement link 15 and another end side of this second interlocking lever 16 is connected to a projected arm 17 projected on the knee-elevating arm 5. It is possible thereby to suppress complication of the mechanism, increasing of the wt. and increasing of the manufacturing cost.