An temperature control unit that is connected to a SSR that switches between driving and stopping of an heater, the temperature control unit comprising: an acquisition unit configured to acquire, from a control apparatus, first information regarding driving and stopping of the heater; and an SSR control unit configured to perform time proportional output of an instruction to drive or stop the heater, to the SSR in accordance with the first information; and the acquisition unit is configured to acquire, from the control apparatus, second information indicating whether or not to subject a time proportional output to the SSR to autonomous control, wherein, if the second information indicates that the time proportional output is not to be autonomously controlled, the SSR control unit is configured to update a cycle of the time proportional output at a timing when the first information changes; the second information takes two values, the two values being ON and OFF; the temperature control unit is configured such that in a case where the second information is ON, the temperature control unit does not autonomously control time proportional output, and in a case where the second information is OFF, the temperature control unit autonomously controls time proportional output; in a case where the temperature control unit autonomously controls the time proportional output, the temperature control unit is configured to determine start and end timings of the time proportional output to the SSR as well as the time proportional output control cycle based on internal information of the temperature control unit; and in a case where the temperature control unit does not autonomously control the time proportional output, the temperature control unit is configured to determine at least one of the start and end timings of the time proportional output to the SSR as well as the time proportional output control cycle based on information that is acquired from the control apparatus. an acquisition unit configured to acquire, from a control apparatus, first information regarding driving and stopping of the heater; and an SSR control unit configured to perform time proportional output of an instruction to drive or stop the heater, to the SSR in accordance with the first information; and the acquisition unit is configured to acquire, from the control apparatus, second information indicating whether or not to subject a time proportional output to the SSR to autonomous control, wherein, if the second information indicates that the time proportional output is not to be autonomously controlled, the SSR control unit is configured to update a cycle of the time proportional output at a timing when the first information changes; the second information takes two values, the two values being ON and OFF; the temperature control unit is configured such that in a case where the second information is ON, the temperature control unit does not autonomously control time proportional output, and in a case where the second information is OFF, the temperature control unit autonomously controls time proportional output; in a case where the temperature control unit autonomously controls the time proportional output, the temperature control unit is configured to determine start and end timings of the time proportional output to the SSR as well as the time proportional output control cycle based on internal information of the temperature control unit; and in a case where the temperature control unit does not autonomously control the time proportional output, the temperature control unit is configured to determine at least one of the start and end timings of the time proportional output to the SSR as well as the time proportional output control cycle based on information that is acquired from the control apparatus.