A cab includes: a pillar member; a beam member; and a rib member. The pillar member extends in an up-down direction. The beam member extends in a left-right direction. The beam member is connected to an upper end of the pillar member. The rib member is provided at a corner portion where the pillar member and the beam member intersect with each other. The rib member is connected to the pillar member and the beam member. The rib member is embedded in at least one of the pillar member and the beam member.