To provide a freeze dry device with a contact/separate mechanism capable of receiving a number of trays, having superior heating efficiency, minimizing a vacuum pumping device to 1/2 on the basis of dehydration amount, and being easily cleaned.

A drying can 6 has a sealed structure composed of a fixed cover portion (cold trap 1) and a moving overcoat can 8, the moving overcoat can 8 is movable to a position to completely expose a multistage multi-heater block 15 to a fixed cover portion 1, a moving mechanism is disposed to move the moving overcoat can 8, the multi-heater block 15 is provided with an upper heater 16 and a lower heater 16 in such a state that the upper heater 16 can be kept into contact with and separated from the lower heater 16, and the contact/separate mechanism is disposed to allow the upper heater 16 to be kept into contact with and separated from the lower heater 16.