A method of controlling the lifting of bottom sections of lying furniture such as a bed that has a back bottom section for lifting the back portion of a lying person and a knee bottom section for lifting his/her knee portion, in which the respective bottom sections can be lifted by the lifting mechanisms respectively provided for them, characterized in that the respective bottom sections are so constituted that they can be operated selectively either respectively independently or in an interlocked manner in response to the command issued to a control means from an independent operation switch for operating each bottom section concerned independently or from an interlocked operation switch for operating the bottom sections in an interlocked manner, and that if the control means receives an interlocked operation command from an interlocked operation switch, it actuates the respective lifting mechanisms for operating the respective bottom sections in an interlocked manner, subject to the condition that commands are not issued from plural control switches.