In an engine valve, a first sliding area formed at a valve head side in an outer face of a valve stem, and sliding along a stem guide, a second sliding area formed at an opposite side from the valve head side, and sliding along the stem guide, and a first small diameter area formed between the first sliding area and the second sliding area are formed. Further, in the engine valve, a length, in an axial direction of the valve stem, of the first sliding area abutting on the stem guide at a position where the engine valve is fully opened is longer as compared with a length, in the axial direction of the valve stem, of the second sliding area abutting on the stem guide at a position where the engine valve is fully closed.

In an engine valve, a first sliding area formed at a valve head side in an outer face of a valve stem, and sliding along a stem guide, a second sliding area formed at an opposite side from the valve head side, and sliding along the stem guide, and a first small diameter area formed between the first sliding area and the second sliding area are formed. Further, in the engine valve, a length, in an axial direction of the valve stem, of the first sliding area abutting on the stem guide at a position where the engine valve is fully opened is longer as compared with a length, in the axial direction of the valve stem, of the second sliding area abutting on the stem guide at a position where the engine valve is fully closed.

A wear-resistant copper-based alloy includes: at least one selected from the group made of molybdenum, tungsten, and vanadium and niobium carbide; chromium in an amount of less than 1.0% in terms of wt %; and a matrix and hard particles dispersed in the matrix, in which the hard particles include niobium carbide and at least one selected from the group made of NbCMo, NbCW, and NbCV around the niobium carbide.

A wear-resistant copper-based alloy includes: at least one selected from the group made of molybdenum, tungsten, and vanadium and niobium carbide; chromium in an amount of less than 1.0% in terms of wt %; and a matrix and hard particles dispersed in the matrix, in which the hard particles include niobium carbide and at least one selected from the group made of NbCMo, NbCW, and NbCV around the niobium carbide.