A catheter includes a shaft and a hub that are firmly fixed to each other. The shaft is a tubular body in which a lumen extends throughout the shaft from a distal end to a proximal end. The shaft includes a shaft proximal surface at which the lumen opens and a shaft outer surface that is an outer peripheral surface of the tubular body. The hub is attached to the proximal end of the shaft. The hub includes a tubular accommodation unit configured to accommodate the shaft. The accommodation unit includes a hub melted surface directly welded to the shaft outer surface, and at least one of the accommodation unit and the hub is formed with a plurality of cavities at a position close to the hub melted surface.