Abstract: A risk analysis support device that performs risk analysis with a short analysis time includes: a control structure diagram input unit which receives an input of a risk analysis target represented in a form of a control structure diagram that represents the risk analysis target by a block and a control showing a relationship between a block executing control and a passive block controlled by the block. A control loop search is performed in a database for a similar control structure diagram including a subset of controls that matches or is similar to a subset of controls extracted from the control structure diagram input by the input unit and acquires from the database a hazard scenario including a node having a correspondence relationship with a subset of controls included in the similar control structure diagram. A recommendation output unit outputs the acquired hazard scenario in a tree structure.