TERMINAL BLOCK

A terminal block is provided with a housing including a connecting surface to which an electromagnetic relay can be connected. The housing has attachment grooves which open in the connecting surface and which extend toward the inside of the housing, wherein the attachment grooves include an attachment groove having a first groove portion and a second groove portion which are disposed adjacent to one another and which communicate with one another. The first groove portion includes a first narrow portion disposed close to the connecting surface, a wide portion disposed farther from the connecting surface than the first narrow portion, and a step portion which is provided at a boundary of the first narrow portion and the wide portion, and which is capable of restricting movement of a retaining member in a withdrawing direction from the inside of the housing toward the outside of the housing. The second groove portion is configured to be capable of accommodating a hook portion of the retaining member without caus