A micromirror device (2, 2A) comprising: a mirror portion on which a reflecting surface for reflecting incident light is formed; a first support portion that is connected to the mirror portion on a first axis (a 1) located in a plane including the reflecting surface of the mirror portion in a stationary state, and that swingably supports the mirror portion around the first axis (a 1); a pair of movable frames that are connected to the first support portion and face each other across the first axis (a 1); a second support portion that is connected to the pair of movable frames on a second axis (a 2) which is located in the plane including the reflecting surface of the mirror portion in the stationary state and is orthogonal to the first axis (a 1), and that swingably supports a movable portion including the mirror portion, the first support portion, and the pair of movable frames around the second axis (a 2); a driving portion (24, 25) that surrounds the movable portion and has a gap with the second support portion on the second axis (a 2); the second support portion having a swing shaft and a pair of coupling portions, wherein the pair of coupling portions couple the second support portion and the driving portion (24, 25); and a fixed frame that is connected to the driving portion (24, 25) and surrounds the driving portion (24, 25), characterised in that, in a state where the mirror portion rotates around the first axis (a 1) and an absolute value of a rotation angle is larger than 0 degrees, assuming that, in a plane orthogonal to the first axis (a 1) and including the second axis (a 2), a distance between an intersection between the second axis (a 2) and a straight line (α) located on a surface of the second support portion and including each end point of the second support portion and an end part of the second support portion on a mirror portion side in the stationary state is denoted by A, and a total length of the second support portion in a direction of the second axis (a 2) is denoted by L, a relationship of 2/3 < A/L is satisfied. a mirror portion on which a reflecting surface for reflecting incident light is formed; a first support portion that is connected to the mirror portion on a first axis (a 1) located in a plane including the reflecting surface of the mirror portion in a stationary state, and that swingably supports the mirror portion around the first axis (a 1); a pair of movable frames that are connected to the first support portion and face each other across the first axis (a 1); a second support portion that is connected to the pair of movable frames on a second axis (a 2) which is located in the plane including the reflecting surface of the mirror portion in the stationary state and is orthogonal to the first axis (a 1), and that swingably supports a movable portion including the mirror portion, the first support portion, and the pair of movable frames around the second axis (a 2); a driving portion (24, 25) that surrounds the movable portion and has a gap with the second support portion on the second axis (a 2); the second support portion having a swing shaft and a pair of coupling portions, wherein the pair of coupling portions couple the second support portion and the driving portion (24, 25); and a fixed frame that is connected to the driving portion (24, 25) and surrounds the driving portion (24, 25), characterised in that, in a state where the mirror portion rotates around the first axis (a 1) and an absolute value of a rotation angle is larger than 0 degrees, assuming that, in a plane orthogonal to the first axis (a 1) and including the second axis (a 2), a distance between an intersection between the second axis (a 2) and a straight line (α) located on a surface of the second support portion and including each end point of the second support portion and an end part of the second support portion on a mirror portion side in the stationary state is denoted by A, and a total length of the second support portion in a direction of the second axis (a 2) is denoted by L, a relationship of 2/3 < A/L is satisfied.