Provided is an availability analysis device and the like capable of analyzing availability even when a system of interest is large. An availability analysis device (151) includes an analysis unit (152) that: calculates a value concerning an interval between two states included in a plurality of states on the basis of (I) component information representing a transition rate in the interval between states of components included in a system of interest, (II) defect information including a condition representing a component state in the case of a defect state representing a state in which, among a plurality of possible states of the system of interest, the system of interest cannot operate, and (III) recovery information including a transition rate in the case of transition of the system of interest from the defect state to an operating state representing a state in which the system of interest is operating; calculates a probability of the system of interest being in a certain state on the basis of the calculated
