A trigger switch has a case member, a cover member, and an operation member configured to be used to carry out an operation. The case member and the cover member are combined with each other to form a waterproof case. When the operation member is operated, the operation member is displaced inward of the waterproof case. An internal pressure of the waterproof case changes in accordance with displacement of the operation member. The case member has a case base that is made from an inelastic body. The case base does not deform in accordance with a change in internal pressure of the waterproof case. The case base has at least one hole part. The case member has at least one deformation section that seals the at least one hole part. The deformation section is made from an elastic body.