To provide a soleplate that contributes to improvement in workability on constructing a building and is available for preventing materials and tools from being soiled and from soiling the building resultantly.

A plate body 11 constructing a soleplate is formed in a flat square shape, and a pair of engaging protuberances 20 each in a U-shaped section are formed in projection respectively at ends on opposite sides of the plate body 11. Connecting protuberances 22 are formed in bulging at the ends on other opposite sides of the plate body 11, and engaging slots 21 are bored in penetration to the connecting protuberances 22. Adjoining soleplates can be connected with each other with the engaging protuberances 20 engaged from below with the engaging slots 21. Holding slots 14 are formed at a surface plate 12 constituting the plate body 11, and the soleplate is fixed to the ground with piles inserted through the holding slots 14. The soleplates are connected with one another and laid around a lot of a building.