Load driving device and load driving method

A load driving method by a load driving device having a relay,

• wherein the load driving device comprises a driving portion configured to drive the relay so that a contact of the relay enters a closed state or an open state,
• the load driving method comprising,
• a driving control step of outputting a closing command for bringing the contact to the closed state to the driving portion, and also outputting to the driving portion alternately the closing command and an opening command for bringing the contact to the open state until current runs through the contact;
• a number-of-retries obtaining step of obtaining, as a number of retries, a number of times that the opening command and the closing command were repeated until the current runs through the contact after the closing command has been outputted to the driving portion at the driving control step;
• and
• a usable period estimating step of estimating a usable period of the relay in accordance with the number of retries.