Provided is a fixed-state testing device including a pressing part that presses a battery, a load detection part that detects a pressing load with which the battery is pressed, and a determination part that determines whether the state of fixing of the battery to a retention hole is good or bad. The determination part determines the fixed state of the battery to be good when the battery is able to maintain the pressing load within a first test load range for a first pressing time and, moreover, to thereafter maintain the pressing load within a second test load range of which an upper limit load is smaller than a lower limit load of the first test load range for a second pressing time.