To provide a medical diagnostic apparatus, securing safety in diagnosis using a microscope, or including a microscope capable of securing the accuracy of focusing as well.

This medical diagnostic apparatus A includes: a medical treatment bed 1 enabling at least elevating operation; a microscope unit 2 including a microscope body 20 capable of moving to a predetermined medical treatment zone Z on the medical treatment bed 1; and a control part 7. The apparatus A includes a detecting means 6 for detecting whether or not the microscope body 20 is located in the predetermined medical treatment zone. The control part 7 controls the operation of the medical treatment bed 1 according to a predetermined operation mode when the operation of the medical treatment bed 1 is designated while the detecting means 6 detects that the microscope body 20 is located in the predetermined medical treatment zone Z.