A collision energy absorbing device of a railcar includes: at least one outside plate constituting an outer tube having 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 at least one outside plate, the at least one partition plate fixed to the at least one outside plate and dividing the internal space. An end portion of the partition plate which portion is located at an end in a direction perpendicular to the axis is sandwiched by the at least one outside plate and constitutes a part of the outer tube.