To provide a trunnion type gas spring having high rigidity of a trunnion shaft periphery even with a compact structure, capable of maintaining high squareness, and having superior durability.

The trunnion type gas spring 1 includes a cylinder body 2, a gas containing chamber 3 formed in the cylinder body 2 and containing compressed gas, a piston part 5 receiving gas pressure of the compressed gas of the gas containing chamber 3, a piston rod 6 extending from the piston part 5 to an exterior of the cylinder body 2, and a trunnion shaft member 10 provided in the cylinder body 2. The trunnion shaft member 10 includes: a trunnion shaft body 21 having an axis 21a orthogonal to an axis 6a of the piston rod 6, provided so as to pierce the cylinder body 2 and the gas containing chamber 3, and joined with the cylinder body 2; a pair of trunnion shafts 22 integrally projecting from both ends of the trunnion shaft body 21; and a through-hole 23 formed in the trunnion shaft body 21 and inserted with the piston rod 6 so as to freely reciprocate.