Spring member

A spring member for being provided between two pressed bodies facing each other in a first direction, the spring member comprising

• a plurality of base plates stacked in the first direction, wherein
• each base plate is provided with a plurality of spring protrusions configured to protrude toward either one pressed body of the two pressed bodies and to press the two pressed bodies in directions such that the pressed bodies move away from each other in the first direction,
• between two base plates of the plurality of base plates adjacent to each other in the first direction, a base plate positioned closer to the one pressed body is provided with an insertion hole into which a spring protrusion of the other base plate is inserted in a state of penetrating the insertion hole in the first direction, and
• among a plurality of portions in an along-plane direction along a plane orthogonal to the first direction provided with the plurality of spring protrusions, a spring constant of at least one portion is different from a spring constant of another portion.