A floor mat suitable for use in a working machine including: a floor portion ; a wall portion arranged on a circumferential portion of the floor portion ; and an opening portion arranged on a part of a first connecting portion connecting the wall portion to the floor portion , the floor mat comprising: a mat main body arranged on the floor portion ; a covering portion configured to cover the opening portion ; and a second connecting portion configured to connect the covering portion flexibly to a circumferential portion of the mat main body , wherein the covering portion includes: a first cover wall portion having: a side portion connected to the second connecting portion ; characterised by a first opposite side portion and a second opposite side portion each extending from end portions of the side portion and being opposite to each other; a second cover wall portion extending downward from the first opposite side portion ; and a third cover wall portion extending downward from the second opposite side portion , and wherein a length of the second cover wall portion from a portion connecting to the first opposite side portion to a lower end portion of the second cover wall portion is equal to or less than a thickness of the mat main body , and a length of the third cover wall portion from a portion connecting to the second opposite side portion to a lower end portion of the third cover wall portion is equal to or less than the thickness of the mat main body . a mat main body arranged on the floor portion ; a covering portion configured to cover the opening portion ; and a second connecting portion configured to connect the covering portion flexibly to a circumferential portion of the mat main body , wherein the covering portion includes: a first cover wall portion having: a side portion connected to the second connecting portion ; characterised by a first opposite side portion and a second opposite side portion each extending from end portions of the side portion and being opposite to each other; a second cover wall portion extending downward from the first opposite side portion ; and a third cover wall portion extending downward from the second opposite side portion , a first cover wall portion having: a side portion connected to the second connecting portion ; characterised by a first opposite side portion and a second opposite side portion each extending from end portions of the side portion and being opposite to each other; a side portion connected to the second connecting portion ; characterised by a first opposite side portion and a second opposite side portion each extending from end portions of the side portion and being opposite to each other; a second cover wall portion extending downward from the first opposite side portion ; and a third cover wall portion extending downward from the second opposite side portion , and wherein a length of the second cover wall portion from a portion connecting to the first opposite side portion to a lower end portion of the second cover wall portion is equal to or less than a thickness of the mat main body , and a length of the third cover wall portion from a portion connecting to the second opposite side portion to a lower end portion of the third cover wall portion is equal to or less than the thickness of the mat main body . <EOS>