To provide a stepladder with enhanced rigidity of a front part main leg body and enlarged tread of a step board to the utmost.

The upper end part of the front part main leg body 5 with step rods 3, 4 fittingly fixed in a plurality of upper and lower stages between a lateral pair of vertical frames 2, 2, and the upper end part of a rear support leg body 9 with cross bars 7, 8 fittingly fixed between a lateral pair of vertical rods 6, 6, are pivoted to each other changeably into an open leg attitude and a closed leg attitude. The front end of the step board 11 is pivoted to the rear side end of the upper stage side step rod 3 in the front main leg body 5, and the step board 11 and the rear support leg body 9 are interlockingly connected by a connecting member 12 so that the step board 11 can be changed into a horizontal position when both leg bodies 5, 9 are opened, and into an upward turned and folded position when both leg bodies are closed.