Attachment tool, attachment method, and multiple-optical-axis photoelectric sensor

An attachment tool for attaching a housing of a light curtain forming a plurality of optical axes along a longitudinal direction to a base,

• the housing having a side wall portion substantially parallel to the optical axes in sectional view orthogonal to the longitudinal direction,
• the attachment tool comprising:
• a base portion having a rear surface or a side surface attached to the base and configured to receive the housing from a front side;
• temporary fixing portions configured to temporarily fix the housing to the base portion by elastic support;
• and
• a full fixing portion configured to fully fix a rotational position of the housing around an axis and an upper-lower position in the longitudinal direction by pressing the housing in a state where the housing is temporarily fixed to the base portion,
• wherein the base portion includes rotation restricting portions that restrict rotation of the housing around the axis to a predetermined restricting range by abutting on the side wall portion of the housing in a state where the housing is temporarily fixed to the base portion.