To prevent the problems of wear, or the like, of a track without increasing the number of installed power sources in a sterilizer having the track in an oven.

The sterilizer carries out the sterilization by storing a material to be sterilized in the horizontally long retort oven 1 having a door 8 on a side face, and heating the material to be sterilized in the retort oven. The retort oven can store two or more racks 2A/2B on which the materials to be sterilized are arranged, in series therein, and the track 4A/4B for conveying the racks 2A/2B is laid on the bottom part in the retort oven. The track is divided to two or more units, and a power source 6 is installed in the track A at the door side. A device 7 for cutting the power transmission for carrying out the transmission and cutting of the driving power from the power source 6 is installed in the track B at the end side.