A collision energy absorbing device of a railcar includes: an outside plate constituting an outer tube including an axis extending in a car longitudinal direction; and at least one partition plate extending in the car longitudinal direction in an internal space surrounded by the outside plate, the at least one partition plate fixed to the outside plate and dividing the internal space. An outer shape of the outer tube is a shape that is symmetrical with respect to a virtual horizontal surface including the axis, and the at least one partition plate includes a missing portion in the internal space.